I wonder if part of it is that it's easier and easier for young people to start companies. 15 years ago, you needed to raise millions of dollars and buy a bunch

I wonder if part of it is that it's easier and easier for young people to start companies. 15 years ago, you needed to raise millions of dollars and buy a bunch of hardware, and (I think) founders tended to skew a bit older. Now that lots of founders are in their 20s, the tech center has shifted a lot toward the places they want to live -- and San Jose is not where the cool kids want to be. To be honest, neither is Mountain View, which is why SF has gotten so much startup mind share over the last 10 years.