> usually people with advanced degrees from hard-to-get-into colleges and years of experience along with very specialized knowledge.

Maybe 2005 Google, but not anymore. A good bachelors degree or enough YoE at most companies gets you the interview, and then the interview result usually does the rest. Those are the "line engineers" that move on to other faangs or unicorns when psychological safety becomes an issue.

Typically it's the people from the hard-to-get-into colleges, or with years of company tenure, or with specialized knowledge causing the psychological safety issues.