Just because its a lot of people there, it doesn't mean a lot of them love hip hop, and are creative. If you are a NYC head, you know how much people want to look like they have money, and that plays a big part in the type of music being created, and how its heard to the public. In other words, the artsy of the old NYC is not really in NYC now because everyone has to spend way too Much money to keep up with the Jones's. That means less love for the art, and more to get a quick buck.
Until someone can supply banging beats at a low cost to numerous artsy NYC artists, nothing is going to change, and NYC artist will be following what is hot, so they can get some money. It will be a producer who will change the NYC for rap music scene, not a rapper or fake DJ. The thing is this producer will need to have money or not care too much about living well because, he will need to find a way to survive in costly NYC. Back in the day, an artist can survive, and make music. Now, gtfoh.
He will also need to market his music outside of NYC, and people who listen to the radio because those type of people don't support what's new, just what's popular. Look at all the new artists who make it big from NYC, most of them get deals outside of NYC, then go back once big.