He is considered to be the Mozart of chess. Was he a child prodigy, or a person with some degree of talent coupled with lots of hard work?
The most important talent is capacity for hard work. That's at the core of Mozart's talent, as well as Michael Jordan (though it helps to be tall), Magnus Carlsen, and probably every child prodigy who achieves anything as an adult.
I disagree with that. Talent is something different. Mozart, Carlsen, tons of great mathematicians I know just have something different in their brains than normal people. Jordan's talent is a bit different as physical talent really requires tons of hard work or it is squashed by those with talent and hard work.
Mozart is a product of the best music education available in Europe in his day. This education began early in his youth. Would anyone with the same education have achieved what he did? Probably not. Was his achievement solely the product of "talent" apart from effort? Certainly not.
Capacity for work, persistence, drive, ambition: these are all elements of talent. These are the most important elements. Does that render genetics (or some other cause of in-born gifts) irrelevant? No.
Why do most child prodigies achieve nothing as adults?
When you are six and play the violin as well as a seventeen year old, yoiu are a prodigy. Composing a symphony that folks will perform centuries after your death is a whole other matter. Mozart played the violin early, but he also spent 10,000 hours mastering his skills before he composed original music.
Carlsen is a child prodigy with a gift for memory, as well as a strong work ethic. His achievements in adulthood put him at the top of his profession. He will get better, too.
The prevailing argument is that talent is an innate characteristic that can easily be stunted by environmental factors.
Michael Jordan will not be as good a basketball player if he was high, never worked out, and was intoxicated during games. Carlsen will not be a good chess player if he never learned how the pieces move.
If you do not recognize that some kids grow up ahead of others, then you're fooling yourself. We're referring to those kids that graduate college at 12, composed a symphony while other kids were playing the triangle, dunked a basketball while others just learned to dribble without carrying the ball. Amazing stuff like that. Carlsen just so happened to have a particular talent for chess, but that talent would never have been realized if he were hit in the head in a car accident and became a human vegetable. Those are extreme environmental factors. Now if you considered more subtle environmental factors like rearing techniques, socioeconomic status, nutrition as pertaining to physical and neural development, etc, it's pretty clear that talents aren't a guarantee for success.