It's because the tech community in NYC has been very outgoing and aggressive in sharing all the awesome things they're doing.
The Hacker culture is already awesome but keeps getting awesomer. People are hanging out, sharing idea and building things because they want things to be awesome.
Other cultures have vibrant communities too. Designers. Thinkers. Financial. Branding. Services. Everyone has a network that's accessible and self-selected into outgoing, aggressive creators.
It's not often that people are so motivated, but it's happening in NYC right now.