Having now been around the NYC startup scene a bit, it's a very different scene than SF and others. NYC's scene really focuses on product companies and companies that fit into finance and big company workflows. Aside from Google, Facebook, and the finance industry, there's very little R&D in many of these companies. NYC's history with IBM and Bell Labs means that it's also not a terrible place for some technical infrastructure companies.
It's not surprising to have a bunch of AI there, because most of the AI scene is sort of perfunctory technical infrastructure around hosting Nvidia GPUs (Lambda, Coreweave, etc.) and end products.
New York was also a great place to host GPUs and ASICs for cryptocurrency mining 5 years ago, incidentally, and there is a lot of infrastructure both in terms of datacenters and old industrial plants that can be converted into datacenters.