Tech recruiter here in Switzerland with ~10 years of experience: People quit their teams/bosses, rarely do they quit for other reasons, like compensation or brand.
I think FAANG employees don't quit over compensation or brand. But I think employees of more normal companies do. A lot. And there's a lot more of them.
Hum, our CEO said something along these lines at the last All Hands.
I don't really know where he got that... I always liked my coworkers and I had the chance to have consistently amazing managers, but I still left previous jobs because was bored to death or got a better opportunity career or money-wise.
There are definitely some types that only care about their colleagues and bosses (I talked to one in my team just recently), but that's probably not even the majority. These people probably tend to stay a loooong time so maybe they are more visible to the execs?