> Also, the idea that chess is a good proxy for genius is a bit out of date.

He wrote that the reason he chose chess was because it was objectively measurable. You play the game, you either win or you lose; there is no way to dispute the outcome.

Imagine that you have dozen children, each of them genius at something different, and that you are surrounded by people who want to prove you wrong. Whatever the artistic genius does, the people who hate you can simply say "yeah, he did something technically impressive, but it's lacking the... nebulous artistic qualities that only we can judge... therefore, not a true genius". Now the chess genius comes and wins every tournament against the adults, there is no way to argue that "yeah, he won all the chess tournaments, but... for some reason we still don't consider him to be a chess grandmaster".