I think the real advantage that the valley has right now is mindshare. This won't change without some prodding. The argument has to be made strongly for New York if this is ever going to change.
"That's a dumb idea"
"Why build Z when X already exists?"
"How does this make money now or ever?"
Yes NY is less likely to have major disasters like web van, but for the same reason it's also less likely to have a google. Only tech cultures that are as crazy or crazier than SV can hope to beat it.
People in NY may be very open to stuff like fashion, but imo they're very close minded when it comes to tech.