The US has the best sports in the world? Gee baseball has some pretty dominant players from other countries, our pro hoopsters seem to struggle when they play against european teams and have to follow the rules that were invented here like not travelling. The only one i will give you is football because it isnt played elsewhere and if it is (canada) it is played by guys who couldnt make it in the nfl.
Very good article in espn mag written by an NBA player that may shed some light--he reaches the conclusion that the real problem with american sports is that our coaches tend to live off their players natural abilities rather than trying to develop new abilities and skills. Ever hear of Dirk Nowitzki? He was a soccer star before turning to basketball. What makes him unique is that he can dribble, shoot, AND rebound despite being almost 7 feeet tall. Heck Shaq can rebound but he cant even walk without tripping over his feet. Why because all of his coaches from youth up saw a tall guy and stuck him in the middle to rebound and never taught him other skills.
I will stop rambling but my point is HS is the only place (with theexception of private schools) where coaches have to work with what they get. CLub,academy, college etc.. always try to find players and plug them in to certain positions instead of training them to play the game at any position.