That said, many hackers just aren't into the sort of startup projects that get funded and pay well in NYC. That's a bigger factor in the "talent shortage." The startups there just aren't that cool. If someone in Brooklyn started a company making life-sized Gundam robots you could control with your web browser, everyone would quit working at whatever foodie-blog-ad-network they're currently stuck at and work at the robot place for half their previous salary.
It's hard to do outsourced work in an early stage startup because stuff changes so frequently. The last startup I worked for in NYC actually did have a half dozen outsourced employees in places like Oregon and Hawaii and all but one of them quit because they were so frustrated about changing priorities and miscommunication.