Also the big tech companies only need "world class" developers in under 10% of their positions. Reducing latency on Oculus Rift? OK you need a Carmack. Building a compliance portal for some new law passed in Kerblachistan? A lot of people can do that, and a company like Facebook has a lot more of the second type of problem than the first.
That's a real understatement. Privacy and legal compliance toward evolving laws in a massive codebase + many datasets spanning multiple complex systems is a company-wide effort that takes some serious system engineering ingenuity. Some of the smartest people at these FAANG companies are currently working on privacy engineering.