I think it's all about being at the right situation at the right time. Starting intense training at a very young age --> Having the right trainers and training methods --> Then continue the full time training into adulthood.
But that's a huge sacrifice to make in terms of social life and having to give up other passions/goals, and chess isn't the most financially rewarding thing. I have alot of respect to for those guys at the top, but it's definitely a tough path, especially thinking of what to do in life outside of chess.
Has anyone tried being a Super Georgeous Master? :)