I think chess much like life is heavily reliant on the opening... if a foundation is not laid early it is much more difficult for a persons mind to attain greatness in chess. If you consider how spongelike a childs brain is and the number of years it takes a "normal" child to reach a great ranking and then consider how much longer it could take an adult new to the game to commit themselves to learning the same amount of knowledge.
In some ways I think you could say that the way chess pieces move and create problems is almost like a language. Something that children are able to pick up and become naturals at far more effectively than adults.
That is not to say that I think a person without a foundation in chess thinking is going to be unable to reach master level. Just all the kids have a head start on you :P
I'm currently reading art of learning by Waitzkin which touches on this idea slightly. I highly recommend this book to anyone :P
What makes a chess genius? Is it a greater working memory than normal people, or just that having been taught the game at such a young age and having studied it so intensely, they have developed an ability to read much deeper into the postion- for example Capablanca said that he only looked one move ahead, but the move he chose was always the right one. Does it come from nature or nurture? If it is down mostly to natural talent (probably the case) what hope is there for the rest of us? Does anyone think that even with say, several years of dedicated study, a player with decent ability can ever hope to obtain an IM or GM title or are they forever out of reach?
Sorry about the numerous questions in this one post, but it's a topic with endless talking points. Any comments will be much appreciated.