I don't get to watch the NBA much admittedly, but I really don't think this is true.
Its not true. The NBA has more talent and more skill now than ever before by a HUGE margin. Players are taller, faster, stronger, and can jump higher, but they also dribble better, pass better, and shoot better. There are only a handful of players in the NBA who can't handle the ball, pass, and shoot from three now. There used to be two or three guys like that in every starting line up.
This is only logical, the NBA has a wider talent pool to draw from now. More American kids are playing basketball than ever before (much fewer are playing baseball, and you'd be a fool to choose football over basketball when skilled enough to play either), and now the NBA is drawing from all over the world, instead of just America.
These discussions drive me nuts. College basketball has ZERO say about the one and done rule. They can't stop kids from going to the NBA and making money. Its an NBA rule that is collectively bargained between the owners and the players association. Nobody else gets a say in this.
I understand why the NBA instituted a one and done rule. It sucks to scout high schools, and they were making too many mistakes, and drafting high school busts way too early. The one and done rule seems to have fixed that issue. You are never going to hit 100% or even close to it when scouting, but when you give the scouts a year to watch players in college the number of kids they miss on goes way down. This rule is working for the NBA, I have no idea why they would change it.
And just for the record, the level of college basketball play has not gone down, its gone up . . . its just become more defensive. The athletes are better now and the coaching is far more sophisticated, thus the defense is on a whole new level. Combine that with the most talented players leaving young (before they truly learn how to beat those improved defenses), and you get lower scoring games. This might not be your thing as a fan, but, its not the result of worse play, or even worse offense, its the result of better defense.
AAU is far from perfect, I understand this, but even with the flaws, basketball players and basketball as a whole is far superior to even 10 or 15 years ago.