Earlier quoted context omitted.
Of course, it's not so cut and dry. It's sort of cyclical IMO: - There are already a ton of existing technology companies in the Bay Area, and also a ton of employees. - Students from schools around the country who are interested in tech might plan to move to the Bay Area due to the number of companies there. - If your company doesn't hire in the Bay Area, it may miss out on the chance to hire the employees in the gr…
So no tax or media related incentives to being in the Bay Area? You don't think it's worth more to Google to say: "Our headquarters are in SF" rather than: "Our headquarters are in podunk MT"? I wouldn't be surprised to find out that 90% of the reason FANG companies operate in large metropolitan areas has almost nothing to do with employees and everything to do with global image.
When Intel acquired the AI startup I worked for a couple years ago, they built us a downtown office, much bigger than our team currently needed. Why? Because there are lots of AI people in Seattle who will not move to California, and Intel wants a chance to hire them. But it's still a very small office compared to Intel's global footprint; it does not affect their "image" at all. It's just a practical way of gaining access to Seattle's engineering talent.
It is a simple virtuous cycle. The presence of good jobs draws people who want to work in the field, and the presence of people with experience draws the companies who want to hire them. Geographic concentration is efficient.