The thing is, America just has better ATHLETES though. Athletically Americans have an advantage because sports are huge part of the diverse culture. Case in point, the Olympics. If this was translated to soccer, USA would dominate because of the giant economy and resources to dedicate.
Look at womens soccer, USA regularly dominates it because they invest in it with their population and resources. Proving my point that if America cared about men's soccer it's reasonable and logical to assume they'd be #1. Again though, other countries might not ever be able to beat the women athletes since other countries don't really give them freedom.