In the USA, most athletes never even find out if they're good at soccer because they start out playing other sports. A guy who might have been the best soccer player in US history probably rode the bench on a HS school football team because he was athletic enough to make the team, but not built right for football. He simply never knew he had the potential in soccer.
India has over a billion citizens. Why don't they dominate sports with such a giant potential pool of athletes? Because most Indian people never have the chance to find out if they're good at sports due to poverty and other issues.