I don’t know how to put the genie back in the bottle. It used to be high school ball, with its structure, coaching and competition, where players were made. AAU, where it existed at all, was just an unstructured way to play ball in summer. Then it was on to college ball, with highly structured coaching, for a minimum of three years...then to the NBA as a mostly finished product.
Somewhere along the line, AAU was taken over by street agents and shoe companies and over decades they created a loose system that got us to where we are now. Crappy basketball at all levels, HS, college and pro. The only players that look like they have been coached are the Euros.