[ohashi]

He was undefeated for 10 years and you're rationalizing that he somehow isn't the best player because some other guy once lost in this format? And his undefeated streak over 10 years wasn't convincing enough for you?

That just... doesn't make sense.

[somenameforme]

That "some other guy" was the undefeated world champion for 15 years, the world #1 player for 21 years, and more. He was much more dominant than even Magnus. Yet it was a similar story for him where his match dominance ended well before his tournament dominance did. Even after losing the world championship title, he would remain world #1 for about 6 more years.

Maintaining dominance against a peer (and their team) who spend the better part of a year doing nothing but preparing for you, is very different than maintaining it in the relatively far more casual environment of tournaments. And there's a big ego trap here. Quitting is easy, especially when you're on top. Continuing to fight until the day you fall is hard, and requires immense character.