You're right about hard work, but some mountains cannot be conquered. If I train for 800 hours and a genius trains for 800 hours, I will clearly loose. I also don't see many players that can hold their own against a computer program like deep blue and it's successors.
Why Are Some Kids So Good At Chess?

That's easy this new breed of player plays and trains with chess engines offline and online for hours and on the Internet to the point they are conditioned to play like the software programs they are learning from.
Plus they have access to an ocean information and resources online not previously avalible to other generation of players which accelerates their grow at a faster rate than a player who learns the traditional way.

its a good question. im quite young, but have only play 10months.
kids are fast to learn because they can make new nerv paths faster than grown ups.
and they have much time to practise
Good points. I think you're right about the nerve pathways - "neural plasticity" I believe it's called.

1) It's easier to learn things when you are young. Not just chess, anything. Kids pick up foreign languages very quickly, for example.
2) Their brains work faster than adult brains. They can calculate 5 moves deep before I've even looked at the board properly. The counter-balance to this is their lack of experience, and the generalised understanding which develops with experience. Often I can understand more about the position by just looking at it, than the child can by calculating 5 moves deep.
3) As an extension from point 2, they are tactical monsters. One slip against a kid and you are toast.

It's tricky to know if it's a great idea to get kids so immersed in chess at a young age. I learnt at 6, and was ok fairly fast, but never reached a very high standard. I do remember it being good fun though and learning quickly. I could also tell when adults weren't trying to beat me.
My brother learnt at 11 and was much better than me, and I'm sure he's done his 10000 hours, but never been a champion. You have to be pretty good at chess to make a living at it don't you?
I taught my daughter long division at 6, and I think it might prove more useful in the long run (she finishes a maths degree this year) but who knows. It worries me slightly pushing kids down a narrow path at a young age, but maybe that's just me.
Yeah, at my club, I regularly play against a 12 year old that is rated over 2200 USCF. When I look at his tournament history, though, I see that he's played over 700 (!!!) tournaments, dating back to 2005, when he must have been about 5 years old. These parents are getting their kids into lessons, and formally shaping their minds at very early ages to be absolutely fluent with the chess board, and sheer repetition is drilling the game into their minds.
So, sure, part of it is learning at an early age, when your mind is like a sponge... But another part is that extreme repetition, which can even get old dogs to learn new tricks!
A great example of what starting ridiculously young can do, though, is the Polgar sisters - basically the best female players in the world which were, as a sort of experiment by their father, raised from birth to play chess.