To me, "natural talent" means a guy who doesn't really care about chess, learns the moves by himself, starts beating everyone around from day one. This means Capablanca, Sultan Khan, Morphy. None of those "hit the books" types.
Also understanding new aspects of the game, which nobody could grasp before, is a sign of "natural talent", imho. And having a completely "personal" and yet very successful style.
Otherwise there could be no "natural" talent in Chess when Botvinnik first, Fischer later, and Kasparov eventually, completed a process of progressive professionalization of the Chess Player in its development and preparation.
i agree with you, natural talent to me is not just what you have when you start. but what you do with the information you get.
We have to also allow for the likelihood that some natural talents were never discovered.
Imagine for a moment that Shirley Temple had natural talent. Do you think that her parents would have encouraged her to use it and develop it?