I'll provide an example that illustrates both points: me. When I went from Red Hat to Facebook, my already-pretty-good total compensation jumped by almost 50% - more considering how each company's stock performed during the relevant vesting periods. I'm pretty sure there were others around me who had been promoted from fresh-out to my nominal level in a quarter to a half the time it had taken me to build my career. Some of them were quite likely making even more than me despite their narrow experience and resulting unsuitability for the same role anywhere else (a topic for another time).
If my salary curve was a race car, theirs was a rocket ship. The FAANG compensation premium to start fresh out of college might be smaller, but the potential growth over the next several years is much greater than elsewhere in tech ... and yes, recruiters do use that as a lure. Given the uncertainty (and compensation inequity) at startups, working at a FAANG is the most likely route to early wealth for most techies.
Of course, you can also get rich early if you get to put FAANG on your resume and parlay that into an early-employee job at a startup that later hits it big. That's prestige at work but, looking at the attrition/retention rates at FAANG, it seems to be the less common route and therefore I'd guess it's the less common motive.