The simple fact of the matter is that Dempsey, Murray, Mathis,Donovan etc are anomalies in the sport. Most of the best athletes in the US choose the so called "glamour" sports. Could you imagine if Cam Newton had been trained as a soccer player, or Dwayne Wade or Derrick Rose.
Another problem is organized soccer the way it is set up here - like the academy system- we are so caught up with putting the same ages together which causes little or no true development. I visited Liverpool with my son when he was 13. They told him that he was a good as any 13 year old they had seen but said if he stayed in the US he would stagnate. They told us that all of the EPL talent that is identified at an early age NEVER plays with their age, they play against men who are 4,5,6 years older than them. That is why 18 year olds from Europe and South America can compete at such a high level at an age when our best are playing in High School. The Liverpool Academy team made up of 16 and 17 year olds visited here and destroyed a team made up of college stars from Furman,Clemson and USC.
To get a real feel for how poor our development of players is here look at the womens game. We once dominated the game but other countries are quickly catching us. The reason, women in other countries didnt play organized soccer, now that they are and are adopting the training and development of their mens teams they are catching up and passing us. Is any American woman as good as Marta?
Until we can convince a larger number of talented athletes to play soccer and adjust our methods to allow our players to play up not just one age group but several we will always lag behind the rest of the world