It may have more to do with cost structure. FAANGs have a willingness to pay much higher salaries, even if they could've hired for less than half the cost else

It may have more to do with cost structure. FAANGs have a willingness to pay much higher salaries, even if they could've hired for less than half the cost elsewhere so it makes more sense for them to be in the bay area, especially since those are super high margin businesses. YOu'll notice that Amazon, a business where margins are important is notably absent from the bay area.