tier-1 biotech in the bay area (genentech, gilead, etc) pays less than tier-1 tech (google, facebook, etc), but that's mainly because FAAMG pay such absurdly high base salaries.

The difference is less profound for tech folks at biotech companies than it is for biotech people. Certainly when I worked at a biotech startup for a year, after leaving FAAMG, I was able to negotiate the same base salary, but base salary is only a part of total comp...