If you know how to leverage your experience you can literally walk in as the CTO of most small startups if you are an ex-googler and don't act like a drone.
CTO of most small startups don't get paid as well as a typical moderately experienced Google engineer. And the job is a lot harder and higher stakes (which is something that some people prefer and others do not).
As someone who has worked at multiple FAANG companies, I think that is a total exaggeration. What on earth does being Engineer #56112 at Google have to do with someone's ability to be a CTO? We’re talking entirely different skill sets. What does "don't act like a drone" mean? Show me one start-up that will simply let me "walk in as the CTO". Come on!
I think that's true for sure. In fact, I know of more workplaces where when doing the hiring, previous experience with Google is a negative rather than positive, as previous ex-Google employees have introduced more problems than solutions, together with strongly holding a "better than you" attitude towards others.
There is the prestige & benefit of having worked for a FAANG, which, once attained, stays on one's resumé forever, so maybe for some people, tradeoffs that are worth it to attain such a job may no longer be worth it to remain in that job after a few years.
Yeah I think the play is to work for FANG for 1-2 years and then skedaddle really no reason to stay not like they're going to promote anyone to something meaningful unless you are truly a superstar.