The club path straight to the pro game in the USA (until the Academy system is developed) needs to be the path for the best of the best, usually identified at the age of around 15 years old…if the USA wants to stay top of the world. For these players, playing in college is not the best for their development. Look at all the one-and-done college players recently making the move to the NWSL. That trend will continue. However, passing up a degree at Stanford and hopping to the NWSL is, in my opinion, the dumbest decision you could ever make, but that’s for another discussion.
For the remaining 99.995 percent of female youth soccer players, taking the path thru the club system, HS soccer, and the college path is just fine. Yes, a small select of these players will play in the NWSL and possibly play in Europe. 95% plus of this group play club soccer to get recruited to play college soccer. And the benefits of sport stay with them through life.
However, I do disagree with your sentence where changing to age groups versus by grade was a mistake. I know parents who held kids back for an extra year of third or fourth grade so they would have a leg up in sports playing with other kids now in the same grade. Works when the kid is young. But if that developing kid turns pro, age is no longer a factor—you get to go up against some experienced players a decade older than you. And that is why players like Ms Turnbow and hundreds of unmentioned others leave the game for brighter pastures.