Let's see....bad weather, high rent, high cost of living, lots of wall street jackasses, too many damn tourists, and plenty of terrorist threats. And we haven't even started talking about silicon valley's tech culture and close proximity to Asia.
Having a bunch of ways to travel doesn't do any good for people who are spending most of their time holed up in one spot. They won't be flying all over the place.
Night life? Have you MET many geeks? Plus that would cut into work hours.
Drop-off laundry? That means I have to take it somewhere. I'd rather have washer/dryer in the apt., then I don't have to lug it anywhere. Who cares about folding.
A diverse and interesting population -- very few of whom work in or understand startups. You don't have time to socialize anyway, and if you did, listening to people talk about finance or fashion is not "interesting".
Incredible food... This can be had in ANY major city. But nobody in a startup wants a 3 month waiting list to get into NY's trendiest new spot, so none of that stuff matters at all.
Culture... again, staring at a computer all day.
Parks? Yeah, like they don't have that anywhere else.
Not compelling in the least.
Look at Google's perks to get an idea of what developers want. Basically: get everything else out of the way so I can develop! Get rid of interruptions and distractions and extraneous TRAVEL -- I don't want to spend my time carting my jiggly fat physical body from place to place so that I can physically do the same thing in another place.
It's the same for ANY discipline. Olympic swimmers have the same deal -- eat, sleep, train. Being "well-rounded" is essentially training for social skills.
More importantly though, you can get to a lot of Asia from SFO without changing a plane, that's not true of NYC.
You're going to let other people make your living decisions for you?
What is there for developers? Almost nothing, plus high costs.
The Bay area has way better restaurants, culture, diversity and intellectuals plus nearby beaches, mountains, wineries, skiing, it goes on and on.