Currently there are at least 14 professional women's soccer leagues in Europe, six of which participate in UEFA.
The Spanish Women's Liga alone has 16 clubs. For the interest of time lets just say that the other leagues have 10 teams. That is at least 106 professional women's teams in Europe of which at least 66 teams are competing for UEFA bragging rights.
The US has over 300 D1 soccer programs alone. That is huge and we haven't even touched upon D2 and D3 programs. But of those 300 programs only 64 will qualify for the NCAA playoffs. Of those 64 that qualify for the playoffs there are really only ten schools that have a legitimate shot at winning. So roughly 25 D1 programs are not only both really really good, but really consistent over time as well. While we have huge collegiate system most of our USWNT players are coming out of only about 25 regular consistent programs.
D1 soccer is a fall sport while Spain's liga-femenina-iberdrola is a 10 month, 32 game season which can include Champions League and other UEFA tourneys. Assuming growth in the youth game in Europe, I just don't see how our top 25 college programs over the next 10-20 years will be able to keep up with Spain alone not to mention France, UK and other nations. In time one or two of the European leagues will also rise to prominence and concentrating the talent even more while smaller national leagues will become stepping stone leagues just like the men's side.
And do we honestly believe that in 10-20 years youth clubs like PDA will out produce La Masia not to mention the Spanish clubs that are trying to develop kids to get into La Masia?