What on earth happened to Peter Leko?

First question: Of course not!  // Second: As far as I know Anand eats fish but not any other kind of meat. 

anand is pure vegetarian he told me

Yes, many thought Radjabov was a future World Champion 10-15 years ago. One difference compared to Leko is that Radjabov was less stable, never won Linares or Dortmund or Candidates or drew a title match etc. He has also had a rather short "down" period. Radjabov was #4 in 2013 and is #22 now, in the mean time at his worst down to #44 (only below #39 on one list though). But he did recently win Geneva ahead of players like Grischuk, Aronian, Giri and Mamedyarov. But in Radjabov's case the speculations have concerned him being "lazy", having a small child, etc. Talent wise I don't doubt that he is World Champion level.

Leko won Linares ahead of Kasparov, had a plus score against Kramnik the first ten years they faced each other, and just seemed like the only player that was certain to be among those that would take over after Kasparov, Anand, Kramnik and Topalov. 

There's also Morozevich among "the fallen" of course, even if he always was extremely uneven. He never won one of the big top tournaments even if he one day even was #1 on the live rating list and now isn't too far ahead of Leko on it. He is a bit closer to Kramnik and Topalov in age than Leko, and had health problems for many years, often withdrew from tournaments, played eccentric openings etc and never felt like a certain future top player the same way as Leko when both were 20-25.

he needs to Leko of my Eggo

Looking at today’s ratings, Leko is #85 on the live rating list, and he is not particularly old, still in his 30s. The ten years older Anand is #8.

A bit lower down on the live rating list today there are quite a few old heroes between #76 and 96, with Leko dropping out of the top 90:

Age probably matters more nowadays than back when Leko was born (September 1979), and the top seven looked like this at Chessmetrics (different rating system than Elo):

Still some oldies have managed to hang around rather well even today, with Anand, Kramnik, Topalov, Svidler, Ivanchuk and Adams all in the top 40 in spite of being between 42 and 49 years old.

That's right. And he is training Vincent Keymer https://www.vincent-keymer.de

The op has been infatuated with Leko. 

Leko is just over 100 points below his all-time best, in 2005. Not much has happened to Leko except that the best in the world have overtaken him. He's still a strong GM, but the best have gotten better. Leko was quite stable from 2000-2016, but now has lost a bit of his competitive edge.

Nothing magical or catastrophic has happened to Leko.

I was briefly excited about him when I learned he had worked with Fischer for a while. But I got over it forever when he played for a draw as White in a World Championship match and the score was even. 

I didn't read all of the posts in the thread, so my apologies if it's already been mentioned, but maybe he discovered the Peter Principle...

”Leko is just over 100 points below his all-time best, in 2005. Not much has happened to Leko except that the best in the world have overtaken him”

Not the whole truth, if one looks at the older players that were around his level 10-15 years ago. Back then players like Anand, Kramnik, Topalov, Adams, Svidler and Ivanchuk were competing with Leko for the position as Kasparov’s successor as #1. All of them older (up to ten years) than Leko, and all of them also ranked more than 50 places higher than him today. 

So Leko sure has dropped surprisingly fast. When he was around 25 he won not only Linares, Wijk, the Candidates, Dortmund, and drew a title match. In 2005 most people would probably have guessed that he would be much higher ranked today than for example Anand and Kramnik, who were 5-10 years older. In April that year the three were ranked #2, #4 and #6, with Leko in the middle. And on today’s live rating list they are #7, #8 and #91...

”he played for a draw as White in a World Championship match and the score was even”

Well, good luck coming up with some source for that claim :-) Kramnik had draw odds so Leko naturally didn’t want to draw with white when the match was even. Leko only had white twice when the match was even, by the way. In the first game, which he lost, and the seventh, where he was outprepared and took the draw with a dead endgame coming up. And then he won the next game as black. But that was one of the more uninteresting of title matches, given that Kasparov and Anand were the best players back then.

"The source for that claim": Bareev's excellent book on the match.

Jacob Aagaard commented, "Peter Leko has three essential qualities (that I know about). He has a great opening repertoire, he is a greatly gifted technical player and a very nice guy. If he had a good understanding of dynamics as well, he would have been one of the greatest players of our time (rather than just one game away from being World Champion!)." Despite criticism that his style leads to drawish chess, his consistent style has seen him remain in the elite since he was a teenager and win multiple elite-level tournaments.

”Bareev's excellent book on the match”

Bareev was Kramnik’s second and naturally rather biased in his assessments. As in the title of his book, which stated that Kramnik won the match :-)

Currently he's commentating the World Rapid...he may be enjoying a transition to the intellectual side of chess rather than the playing side.

Maybe he got a life.

It could happen.

Leko became a trainer/coach. If you harbour ambitions of your own, it's probably not good for your chess at that level to split your focus. Look at Ruslan Ponomariov. He's done a similar nosedive, and he's doing quite a bit of coaching as well, as far as I know. Clearly, it doesn't help either if you a down period and drop rating points and lose the regular invitations to the top events. Much harder to come back up again.