Opening study = waste of time?

waste of a time if you are going to play 960

Openings are largely irrelevant unless you and your opponent both have pretty good mastery of positional play, strategy, and tactics.

But if you do, then openings become crucial.  It is in this stage of the game when the logic horizon is still so far distant that the only way to try to carve out an advantage is to know the body of work hundreds of years of chess scholars have compiled.

It is precisely BECAUSE there are still so many possible reasonable moves that theory becomes crucial.  Once the pieces develop and clash together, the candidate moves become far fewer in number, and can be analyzed using basic chess fundamentals.  Before that happens, you've got theory, and little else.

studying openings is a waste of time if you cannot reach 60+ in puzzle rush consistently

Usually helps to understand what makes an opening work and how this carries into a middle game.

Interesting

For me opening prep isn't a waste of time.... I'm just too lazy to do it

I thought it was a waste of time learning openings. Then I grabbed a hanging pawn on e4 with my knight, got put in check by his queen, and then my knight was gone. I could have learned that lesson on YouTube where it would not have cost me a game. 

You should know as much opening theory as you encounter, and as a general rule of thumb if you aren't losing out of the opening you know enough. It's also much better to remember ideas and plans than to memorize moves. 

Personal anecdote time. I played the French defense from the range of 1600-1850. Specifically the advanced variation was my favorite to see on the board. What I knew when I started playing the opening was to play 3.c5 and come after the d4 pawn. This concept quickly led me to playing 1.e4 e6 2. d4 d5 3. e5 c5 4. Nc6 c3 5. Nf3 Qb6. And I had ideas of Ne7-Nf5 to add pressure to the d4 pawn. Just knowing this simple plan was very effective from about 1600-1750 or so. However, I found as I climbed the ratings I started encountering a move 6.a6 that I just could not handle. 6.a6 is actually the mainline move, but prior to reaching a certain level my opponents never played it. Once I reached that level I started getting smacked around, I had to hit the books and learn the ideas to handle 6.a6. Prior to that level studying it would have been useless, but at that level it became essential. 

This is how opening study should go in my opinion. Know as much as you need to in order to not lose from the opening. When you start getting hit by more sophisticated ideas then study up on those. No point in memorizing a 30 move najdorf draw when your opponent deviates on move 4. 

Total beginners should only know the first move and opening principles. I would also highly recommend that first move be one of e4, d4, e5, or d5. Early intermediate players who are starting to play more intricate openings should learn the ideas behind them. Nothing is sadder than a "King's Indian" player who never pushes their king side pawns thinking the point of the opening is to hide behind the fianchetto. 

*as I lose all my game due to not knowing opening theory*

#22
"Openings are largely irrelevant unless you and your opponent both have pretty good mastery of positional play, strategy, and tactics."
++ Yes. That is right. "pretty good mastery of positional play, strategy, and tactics" that is what you have mastered when you are a grandmaster.
It is perfectly possible to play even at IM level without knowing any opening theory.
Even more: all time wasted on opening theory is time that could haven been spent more efficiently on tactics and endgames. So some IM became IM because, not despite of not studying openings. GM is another level though.