Is that really the explicit or even tacit goal of USSDA? I'm scouring the DA site and I don't see anything about a specific style of play.
Teams that are trying to win, what they do is limit touches by weaker players and force feed the ball to their best players, who are almost always the most physically mature, strongest, fastest players. Bypassing weaker players results in lots of long ball, or direct play.
This style of play works until u16 because by then all the boys have had their growth spurt and relative age effects and the benefits of early physical maturity are gone. So by u16, the boys need to be able to play a more advanced, sophisticated passing system.
However, it takes years of practice and A TON of talent and kids that have high soccer IQ to make these advanced passing systems work. When kids are learning these advanced passing systems, there will be a lot of losses at the younger age groups, because a lot of kids just don't have the soccer IQ or skills to make these systems work, and weaker players, who typically turn the ball over at much higher rates, are touching the ball more. Even the kids who have the talent to operate a Cruyff style 4-3-3 will still make mistakes and turnovers.
There have been some posters on this board who have ripped teams for not playing advanced passing systems, and booting it to speed forwards. I think that criticism is unfair. The clubs have to look out for themselves, and winning teams make more money, because parents pay for those clubs. If parents paid money to losing teams that strictly enforced Cruyff style 4-3-3, that's what clubs would provide.
I also think there are just a very limited number of kids who have that combo of high level ball skills, speed and high soccer IQ to make these advanced passing systems work. Since so few teams have the talent needed to run the academy 4-3-3, they end up direct passing or longballing to their best players out of the academy 4-3-3 formation. However, I do think there is less longballing and more advanced passing in academy League than in any other league I have seen, except for futsal leagues.