There may be opportunity costs involved, but there is no way FAANG can grab all of the top talent. Some of it is going to make its own way simply because they want to write their own rules.
The few that slip by get acquir-hired in a few years.
They're pricing a budget out to rationalize an equity raise and are completely inept at what is necessary to get their highly specialized engineers.
Sure there are a lot of engineers working at noncompetitive companies making 80-180k and lower outside of the bay area.
But if you expect to spend less time on recruiting and less time on attritition for your skillset that only exists in the bay area or HFT firms, wake tf up!