I think it warrants discussion as to how there has been a decline in the abundance of incredible talent coming out of NYC. Is it that everyone has caught up, or that there is something else? Certainly the radical decline of schoolyard basketball could be a factor. A lot of stars from the past grew up on playgrounds where if you didn't win, you sat. Schoolyard games could become wars, where lesser skilled players would give 150% to stay on the court and wouldn't yield an inch to better players. Sadly those days are gone.
I theorize that there is also a lot of wasted talent. Kids who are very good but don't play because they don't go to school or maintain the grades to be eligible.