Oh but I do care.
"You HAVE to be something special to be as good at it as he is."
Here is just as valid an argument:
"You DON'T HAVE to be something special to be as good at it as he is."
If we are just assuming things, anything goes.
Isn't this common sense? I mean, I have a book by Patrick Wolff. He worked tremendously hard at his chess. Waitzkin did. Alekhine did. Heck, Spassky did too. Yet somehow, none of them were ever as good as Bobby Fischer-perhaps nobody was but Kasparov (debateably). So are we assuming that Fischer just worked that much harder than all of them?
I don't buy it.
And I don't buy arguments founded entirely on common sense (speaking of your argument presented here, not for the nature argument in general).
So you have come up with a little shred of "potential evidence." You've still got a lot of work to do
Estragon: This argument is used a lot, but it doesn't allow for any conclusions because we don't know how they studied, or what their approach was to the game.
Now, if we could see a six year old kid, on his own, reach master in a year, without spending more than three hours a day, then I think that would be pretty conclusive for nature.
In other words, the negative in paragraph one, "training (seemingly) didn't work for most students," is less effective (due to the ambiguity of "training") than the second paragraph, as the second shows an independance between training and high ability. Of course I know that nobody argues for complete independence between the two, but I would imagine they do think that talent without hard work carries you decently far, just not all the way, and for that, I think they are looking for evidence similar to that of paragraph two.