Maybe DA's sense, but certainly not common sense outside their world. There's no hard data, studies, evidence etc. that the more restrictive DA training structure and league format produces better girls/women players. Just US Soccer saying so. In fact, there is proof to suggest that a long-term environment with a little less soccer or a longer break each year reduces burnout and improves injury-risk rates. Burnout especially in SoCal where we have year-round weather and are not forced by Mother Nature into alternative programming like indoor or futsal or cancelled weeks due to snow, etc. Also, factor in that many sports experts are of the opinion that a multisport athlete will be better longer term at soccer (eg, a high school soccer player who also plays basketball, hockey, runs track). Last, consider that all the women on the USWNT to date have made it to their level (better than all the other players in the World) without the current DA program, by playing multiple sports, and with some freedom of personal choice through their teens.
The boys side has a bigger disparity of team quality between DA and ECNL, so I would agree with your past 10 years statement for the boys. But that is beginning to change as well.
ECNL and DA girls are comparable leagues--both having strong teams and weak teams. Both play about an equal number of games throughout the year. Both have college showcases to be recruited into the same programs at the next level. One gives its players a couple more months of freedom away from its league. For girls, that annual personal choice is a value-add in my book. Maybe you disagree, and that's fine, but neither of us can say definitively that one league is or will produce better players than the other. That's marketing hype, which is always easy to fall victim to in our hyper-competitive youth sports scene.
PS - Don't forget to wash your hands