The frame of reference here is important, otherwise average is pretty meaningless since we have no objective list of what an average developer consists of.
As a hiring manager I view Google on someone's resume as a non-signal. If however they are the sort of person who draws attention to having worked at Google I view that as a negative signal.
They were also not "walking in to captain" anything. They were applying for standard engineering jobs. Think of an average individual-contributor software engineer from, say, Facebook. Is a smaller company really going to hire them as Director Of Engineering (a totally different job than software engineering), just because of the company name on the resume? That sounds absurd.
I was very skeptical about this, then I worked for one. Now I get it.
All I see is that faang is a term for expert code monkey.