Silicon Valley != San Francisco. In fact, the idea of San Francisco being a part of Silicon Valley is a very recent one. The article makes some good points. But if you're going to write about Silicon Valley, the first thing you must do is understand what it is.
Yeah, as you can probably tell I struggled a lot with the term "Silicon Valley." I meant to describe more the culture than the geographic place, but since I'm based in SF it all kind of got conflated. Good point, I'm going to think a bit more about how to make that distinction clearer.