Example: I have very poor vision that wasn't diagnosed until I was almost 9; because of that my visualization skills are vritually nonexistent. Its a REAL hindrance to me that I'm working hard to overcome. My wife on the other hand has almost savant-like visualization abilities...living technicolor no less...I tell her she would be an awesome chess player, but...you guessed it...she has zero interest in learning the game.

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Anyway while talent is a factor exposure is far more important. Fischer had 2000s in his backyard since he was 6. Kasparov went to a school dedicated to churning out GMs. The average person doesn't have that. The average person is completely on their own with nothing but tons of information that is mostly useless to them. If you're surrounded by great players constantly then that simply rubs off and it doesn't take much to figure out what you're doing wrong.

That plateau is exactly what happens to most people. They get to a point and then they stall because they don't know what they need to get any better. With no one to ask and tons of misinformation out there they just quit as they reckon that there's no good way to figure out what to do to improve - either that or they simply apply incorrect measures in the hope that change occurs.

What did Bobby and Kaspy do? They tugged on the sleeve of the grandmaster next to them...

I agree, that's why whenever I get a chance to play online against whoever's looking for a game I try to pick someone significantly higher than me...humbling but educational. I'm playing a guy right now a few hundred points higher and the game (5 days per move) has been going on since JULY. I'm up a pawn in the endgame but it'll probably end up drawn. To me that's a victory and an education.

Russia used to teach all the kids chess, and most were seen not to have GM talent.

I've seen that same show several times.  Apparently I'm supposed to be an 800 player and that's all there is to it!  

If you can spell you can get a much higher rating.

You know you can get higher than that if you practice.