This is absolutely not true anymore. Ever since FAANG started layoffs, they've been replacing those SF engineers with ones from middle America. Mid-level engineers are earning about 100k-140k base salary, with a 10-20% annual bonus and up to 50k in stock grants. Some of the top level engineers earn more, but not mid-level. I would cut your numbers in half for a more realistic number.
It turns out paying White engineers from the rust belt is cheaper and more productive than pajeets. They use AI tools to replace the productivity of the streetshitting hordes and there are no visa issues.
Also, the myth of the bay area tech wizard is just a myth. Their performance is mediocre in comparison to their rust belt competition. A lot of them lack useful skills outside of a very limited niche and can't work on smaller teams where more responsibility is required.