Ivanchuk didn't ever retire, that was purely a false rumour by chess journalists. 

http://www.chessvibes.com/reports/a-big-interview-with-vassily-ivanchuk/

trw wrote on 02/27/11 at 20:21:50:


Both I guess. But I suppose for the people who are extremely successful at it and were/are getting paid for it, it seems stranger. 

But it's more like why don't these guys play in tournaments just for fun if nothing else? They could play games on the internet, true. But it's not the same. 

Actually, I'm more surprised that so many people choose to play chess professionally or at least attempt to reach that level. 

That strong players quit happens in all sports, usually due to age or injuries - or simply because they've lost the need to compete. Chess, Football etc are great pastimes but the effort to keep a professional level is so demanding that no one can keep up with it indefinitely. Except Kortchnoi!

Here's a list of people who just gave up chess:

* Garry Kasparov, who was still easily number 1 and making millions at the time.  
* Andrew Soltis, the prolific chess writer who became a GM in 1980 and just stopped playing in the 1980s.
* Susan Polgar, who just stopped playing tournament matches when she was one of the best women in the world. 
* Sofia Polgar, who stopped playing in 2003 and played one FIDE-rated game since.   
* Pal Benko who made the remarkably honest statement: 
"Being a professional player is something akin to being a prostitute: First I played because other people did it. Then I played because I liked to play. And finally I played just for the money. "
* Fischer who.... well, we all know about Fischer. 
* Morphy who quit playing for good at the age of 22 or so (ostensibly because nobody could come anywhere close to matching him). 
* Ivanchuk also quit chess and then made a dramatic return... a few days later. 
  
True you have Victor Korchnoi, Spassky, Sveshnikov and maybe others who keep going, but they are a minority. I think Nigel Short is the oldest player in the top 100.  
   
Could it be that once a chess player realizes or believes he has already hit his peak that they get depressed about their chess play and no longer want to do it, even for money? Maybe some people lose part of their "mind's eye" as they get older and can't see the moves like they used to, feel frustrated, and just quit. 

Kasparov also lamented having to have an encyclopedic knowledge of the opening all the time. It could be that GMs get sick of that.  
   
But is chess something you do for a part of your life, and then give up, never to return or care about again and probably wouldn't even if you were paid to do it? That seems sad....