Well, no... i think it has more to do with coaching and opportunities... soccer guys are different kinds of athletes then basketball, baseball, and football players, with not a lot of crossover, maybe with the exception of corners and wideouts... I would assume at least 90% of the athletes playing soccer, would still be just as successful if the pool of talent to draw from included all MLB, NBA, and NFL guys. The number one trait for a soccer guy to have is speed and the second is probably awareness and IQ. I think really smart guys like Revis and Ed Reed would probably have a lot of success. But there's a reason a midget like Messi can dominate, because size and strength doesn't come into play as much.
But I believe the USA will win a world cup in my lifetime... and then what's the excuse.