This overestimates the role of international soccer in predicting future international soccer success. Players get 99% of their development with their club teams. While it is crucial for Americans to regularly play good teams, this experience is mostly going to happen in top European leagues and the Champions League.
And we're in the midst of a huge boom period for Americans in Europe, with young Americans playing regularly for perennial Champions League teams Dortmund, Barcelona, Chelsea, Juventus, and Leipzig, a handful of starters on quality teams behind them, and major European teams spending more and more resources scouting American prospects.
Player quality is the main driver of international success: Belgium went from 57th-ranked in 2010 to 1st-ranked in 2015 (yes, FIFA rankings are bad, but they point to something real) not because of some change in scheduling philosophy but because they had a bunch of great players in 2015.