The problem is that soccer isn't popular enough with enough kids. The best athletes play football or basketball. When LeBron James, Michael Westbrook, Marshawn Lynch, Calvin Johnson, etc. start playing soccer, we will start winning. In all honesty, right now in the United States, soccer is a sport for middle class kids who can't play football or basketball. Training our mid-tier athletes to death still won't be enough.
that's sort of incorrect. the athletic physical freaks play football or basketball. if you're under 6'1, your chances of making the NBA are slim. If you can't grow to 230-300lbs, or be tall and really fast, football is going to be tough as well.
soccer is perfect for great athletes who don't have the size that basketball and football require.