As someone based in NYC (since 1996) but debating a move to SF, I'd agree. I was here through the .com boom and used to attend NYNMA events (remember those?), but NYC has never really been tech startup-oriented in the way SF is. They've tried, what with billing it as 'Silicon Alley' and all, but it never really seemed to take hold. And the big tech events where they'd have Bloomberg as a keynote and then do a handful of tech demos... the demos would be things that we'd seen before coming out of SF and seemed like copycat products.
A big part of it is the culture here. If you tell someone in NYC that you're bootstrapping a startup out of your living room, the response is 'oh, so you're unemployed'. Do the same in a conversation in SF and people start talking about who might be a good fit for you to meet. So, I wouldn't recommend starting a tech company here.
Don't get me wrong, NYC is a great place for tech. But I'm talking about tech in service to financial services institutions. So, web development, financial software, etc. And mostly around Microsoft tech (ASP.NET, SQL nowadays). I've worked at corporate banks, I've built ecommerce systems, I've built events management systems. They've paid the bills. But the dream change-the-world startup idea? It's just not part of the culture here. Fashion? Absolutely. Food? Sure. Music? Maybe. But tech that's not gonna be a financial services play? I'd suggest looking elsewhere.