And I suppose the obvious answer of "all our best athletes play football or basketball"
No, that's a cop-out answer.
The real answer is that, prior to the recent inception of the youth academies, there was no regimental criteria that the elite youth programs were held to as in Europe. Instead, the best youth teams in the US would hoard the best athletes and not develop their individual technique or soccer brains. Thus, when put in situations when they were matched athletically, their lack of technique and intelligence is exposed. The United States National Team does not struggle because of our lack of athleticism. It struggles because of the ineptitude of our collective approach to soccer. When players are young, the emphasis should be solely on teaching the game and developing skills. When results are the primary objective, player development suffers.
Try telling that to American parents though, when Jimmy isn't on a winning team.
Basically, if their coach is their best friend's dad who yells "Boot it!" or "Nice Kick!" ever during a game, they are not being developed at the level they should be to be successful. Granted, the game is for fun and sometimes playing with your best friends is the most fun, especially when you're young. I just wanted to throw this out there for people to keep in mind if their kid(s) were serious about pursuing the game at higher levels.
Edit: I put this in Random Thoughts because I don't think anyone is really checking the soccer thread religiously.