I feel like the English Attack setups are a significant way for white to lower the theory needed to play Open Sicilians (Still need to study the lines it's a Sicilian after all) While actually being absolutely sound and even almost mainline, while also giving an opposite side castling and pawn storm on the kingside game.
Why is theory so important in the sicilian?

"Why is theory so important in the sicilian?"
For me it's not, lol, I just play the Kan, limiting all my opponent's natural moves, and win lol...

It isn't important unless you play at higher level in which theoretical lines are more important in any opening. If you play it at lower level then no-one knows the theory so well and it's just a game of chess.
There are some people who tell you there's loads of theory and then tell you to play other openings but that's generally just because they don't play the sicilian or they lost a few times in the sicilian and they're salty about it.
Sicilian Najdorf is a very good opening for attacking players at all levels as you get very open, dynamic positions and it's very flexible so you can always have a lot of fun with it.

The Sicilian defense is not really as viable as it used to be your simply studying too much theory grandmasters normally only play it in rapid chess since it's only the fourth best move from theory standpoint

In the open Sicilian white seems to have ample room to play what they want; black plays mostly the same moves regardless of system with a different move order to counter whatever white feels like doing. Black has to be aggressive with fast strikes because structurally the queen side is full of holes. White can play both sides or board thanks to the bishops and queen which are unhindered. But black is usually locked in with one bad bishop or having most of the pieces clustered around the king origin point. (The fianchetto in a dragon at least avoids the bad dark squared bishop.) It is a true battle to gain control. But asymetric games will always require the player not to be passive. Note the same issue can be found in the Dutch, White has lots of freedom, black has to be precise.
The Sicilian defense is not really as viable as it used to be your simply studying too much theory grandmasters normally only play it in rapid chess since it's only the fourth best move from theory standpoint
Not true. Sicilian does better than all of those other openings in terms of wins. Just look at that black bar cutting into the barchart here for 2200+ players.
Now people say people playing the sicilian stats are higher rated players pushing for a win against lower rated ones but this is not the reason for the Sicilian's superiority.
See the columns where it says average rating, performance rating after the count of games in the database? The average player who played the Sicilian was 2427 while the performance rating of the move was 2393 (it's to be expected that this is lower than the average rating since it's black). Meanwhile, the average rating of the people who played e5 is 2451 while the performance rating is 2416. (The reason for why the average rating of the opening is higher for e5 is likely that the very, very high rated players over 2500 say just play e5 more often in general, especially against each other).
Look - remember that they are playing as black so both of them will be expected to score lower performance rating than their actual rating. The point is that e5 has a performance rating of 35 points below what should be expected for the rating he has while Sicilian has a performance rating of just 34 points below what should be expected, ie. the Sicilian is outperforming e5 at the level where both players are above 2200. I don't think you can ask for any more than that.
e6 is at -36, worse than them both, while c6 is also at -35.
As the image is only coming out at low res, here it is in higher res:
https://i.imgur.com/oaZTW3M.jpeg

Hi!
Theory is important when you have forced lines. And the Sicilian is plenty of those lines. For instance, you may not play the ...Qb6 Najdorf or the Dragon if you don´t know its theory at the level your opponent´s do.
Good luck!

once you get used to the smith morra, it's playable, but theory DOES help.
in general, no-one is booked up like sicilian players because it's a very complicated system
Hi!
Theory is important when you have forced lines. And the Sicilian is plenty of those lines. For instance, you may not play the ...Qb6 Najdorf or the Dragon if you don´t know its theory at the level your opponent´s do.
Good luck!
yeah. If you play the sicilian against someone good, rated let's say 200 points more than you, and you don't know the theory as well as they do or are uncertain, then it's game over straight out of the opening.
If you play the Caro or e4 e5 against someone 200 points ahead of you, and you play as solidly as possible, even if they know the opening better than you they could be searching around trying to figure out how to prove advantage, so you still have a chance.
There are a lot of positions in the sicilian as black that look completely normal but are in fact game over for black against a good player.
There's no "winging it" with the Sicilian, but on the plus side if you do manage to outbook your opponent - and by outbook I include knowing the general responses for a position even if not exact moves - you could also score massive wins.
The surest way to be completely slaughtered is to learn a single main line for 20 moves or so and then have no idea what to do because your opponent will have seen this many times.

The answer is far simpler than anyone else is trying to give.
It is THE most common chess game. By far. Other factors don’t outweigh that one crucial fact. The reason Sicilian theory is so important at higher level is the same reason that e4 e5 is so important to U1300 players. It’s essentially all you’ll ever be facing, so it’s the best use of your time from an opening standpoint.

The Sicilian defense is not really as viable as it used to be your simply studying too much theory grandmasters normally only play it in rapid chess since it's only the fourth best move from theory standpoint
Not true. Sicilian does better than all of those other openings in terms of wins. Just look at that black bar cutting into the barchart here for 2200+ players.
Now people say people playing the sicilian stats are higher rated players pushing for a win against lower rated ones but this is not the reason for the Sicilian's superiority.
See the columns where it says average rating, performance rating after the count of games in the database? The average player who played the Sicilian was 2427 while the performance rating of the move was 2393 (it's to be expected that this is lower than the average rating since it's black). Meanwhile, the average rating of the people who played e5 is 2451 while the performance rating is 2416. (The reason for why the average rating of the opening is higher for e5 is likely that the very, very high rated players over 2500 say just play e5 more often in general, especially against each other).
Look - remember that they are playing as black so both of them will be expected to score lower performance rating than their actual rating. The point is that e5 has a performance rating of 35 points below what should be expected for the rating he has while Sicilian has a performance rating of just 34 points below what should be expected, ie. the Sicilian is outperforming e5 at the level where both players are above 2200. I don't think you can ask for any more than that.
e6 is at -36, worse than them both, while c6 is also at -35.
As the image is only coming out at low res, here it is in higher res:
No that's not really true as in the Sicilian white has a lot of space and is slowly suffocating black it's not the best when you need to win if you need to win with black play the alehkines defense or maybe a modern/ pirc just becaus opening has a high win rate doesn't mean it's good

The Sicilian defense is not really as viable as it used to be your simply studying too much theory grandmasters normally only play it in rapid chess since it's only the fourth best move from theory standpoint
Not true. Sicilian does better than all of those other openings in terms of wins. Just look at that black bar cutting into the barchart here for 2200+ players.
Now people say people playing the sicilian stats are higher rated players pushing for a win against lower rated ones but this is not the reason for the Sicilian's superiority.
See the columns where it says average rating, performance rating after the count of games in the database? The average player who played the Sicilian was 2427 while the performance rating of the move was 2393 (it's to be expected that this is lower than the average rating since it's black). Meanwhile, the average rating of the people who played e5 is 2451 while the performance rating is 2416. (The reason for why the average rating of the opening is higher for e5 is likely that the very, very high rated players over 2500 say just play e5 more often in general, especially against each other).
Look - remember that they are playing as black so both of them will be expected to score lower performance rating than their actual rating. The point is that e5 has a performance rating of 35 points below what should be expected for the rating he has while Sicilian has a performance rating of just 34 points below what should be expected, ie. the Sicilian is outperforming e5 at the level where both players are above 2200. I don't think you can ask for any more than that.
e6 is at -36, worse than them both, while c6 is also at -35.
As the image is only coming out at low res, here it is in higher res:
No that's not really true as in the Sicilian white has a lot of space and is slowly suffocating black it's not the best when you need to win if you need to win with black play the alehkines defense or maybe a modern/ pirc just becaus opening has a high win rate doesn't mean it's good
… Are you serious or are you trolling. I REALLY cannot tell. White is slowly suffocating Black in the Sicilian? Just because an opening has a high win rate doesn’t mean it’s good? If you need to win play the Alekhine’s, Modern, or Pirc? The Sicilian isn’t viable on the basis of theory? It’s the fourth best move from a theoretical standpoint? Literally not a single thing you’ve said here is even REMOTELY correct.

The Sicilian defense is not really as viable as it used to be your simply studying too much theory grandmasters normally only play it in rapid chess since it's only the fourth best move from theory standpoint
Not true. Sicilian does better than all of those other openings in terms of wins. Just look at that black bar cutting into the barchart here for 2200+ players.
Now people say people playing the sicilian stats are higher rated players pushing for a win against lower rated ones but this is not the reason for the Sicilian's superiority.
See the columns where it says average rating, performance rating after the count of games in the database? The average player who played the Sicilian was 2427 while the performance rating of the move was 2393 (it's to be expected that this is lower than the average rating since it's black). Meanwhile, the average rating of the people who played e5 is 2451 while the performance rating is 2416. (The reason for why the average rating of the opening is higher for e5 is likely that the very, very high rated players over 2500 say just play e5 more often in general, especially against each other).
Look - remember that they are playing as black so both of them will be expected to score lower performance rating than their actual rating. The point is that e5 has a performance rating of 35 points below what should be expected for the rating he has while Sicilian has a performance rating of just 34 points below what should be expected, ie. the Sicilian is outperforming e5 at the level where both players are above 2200. I don't think you can ask for any more than that.
e6 is at -36, worse than them both, while c6 is also at -35.
As the image is only coming out at low res, here it is in higher res:
No that's not really true as in the Sicilian white has a lot of space and is slowly suffocating black it's not the best when you need to win if you need to win with black play the alehkines defense or maybe a modern/ pirc just becaus opening has a high win rate doesn't mean it's good
… Are you serious or are you trolling. I REALLY cannot tell. White is slowly suffocating Black in the Sicilian? Just because an opening has a high win rate doesn’t mean it’s good? If you need to win play the Alekhine’s, Modern, or Pirc? The Sicilian isn’t viable on the basis of theory? It’s the fourth best move from a theoretical standpoint? Literally not a single thing you’ve said here is even REMOTELY correct.
Alright Mr 1700

I forgot that Community Guidelines nukes posts that contract the words “who” and “are”, so anyways, I’ll paraphrase.
Calling me Mr. 1700 is quite ironic, considering new accounts’ rapid ratings are heavily inflated and my Blitz peak is STILL higher than your Rapid peak.
My current rating is due to my switching to 5|0 to prep for longer games for an upcoming Rapid rating climb, a complete opening overhaul, and a break from chess due to life reasons.
Despite all that, chess.com rating literally has no value at all. It’s just an arbitrary number that has no real-world value, unless it’s above 2200 and you only play 30|0 or longer games, in which case it may actually be accurate to your real-world chess skill.
I have U1000 friends, U1300 friends, and U1600 friends, and the best of us are the ones who have OTB experience, do our own research, put the time and effort in, consume real world chess content, and will still be here decades from now.

I forgot that Community Guidelines nukes posts that contract the words “who” and “are”, so anyways, I’ll paraphrase.
Calling me Mr. 1700 is quite ironic, considering new accounts’ rapid ratings are heavily inflated and my Blitz peak is STILL higher than your Rapid peak.
My current rating is due to my switching to 5|0 to prep for longer games for an upcoming Rapid rating climb, a complete opening overhaul, and a break from chess due to life reasons.
Despite all that, chess.com rating literally has no value at all. It’s just an arbitrary number that has no real-world value, unless it’s above 2200 and you only play 30|0 or longer games, in which case it may actually be accurate to your real-world chess skill.
I have U1000 friends, U1300 friends, and U1600 friends, and the best of us are the ones who have OTB experience, do our own research, put the time and effort in, consume real world chess content, and will still be here decades from now.
I have more otb experience than him so I said that and also no it isnt
Sicilian is sharp like a razor.