I can’t speak to AAU basketball.
But I can tell you that I talk to parents of ECNL soccer players and they all say that soccer is the worst in terms of $ extortion from the parents / gatekeeping out the masses of potential players.
It’s frustrating because the cost I am complaining about probably does benefit my kids because it thins the player pool for them - makes them more competitive. If you let more kids have access to the upper levels of the sport they might get pushed out / down. But it’s still not right.