It's the media hype and coaching, it's why Upstate NY has been producing higher quality players for the last 15 years. There's probably more 6"6+ kids in NYC than any other city in the US, yet none of them develop an actual skillset to talk about. The game in NYC is too focused on small ball and one on one play, it's why all the top recruits from NYC are always these 6"0-6"3 guards with no jumpers and little PG skills.
The highest rated player from NY this year is from Syracuse @ 28, the highest rated NYC player is ranked 39. The highest ranked player for next year from NYC is at 69, shyt is pathetic.
There needs to be a complete change in the basketball culture in NYC, eventually you'll have a 4-8 year stretch where players are really good since things move in cycles. All it takes is 1 or 2 really good players to make everyone else develop at a rapid pace, but without a culture change NYC ball will continue to suck.