Over a career though you'll be at quite a few of them. Figure 7-10 or more in some cases. Some will be quick fails (within a year you know it's just not going to work and you move on) and others will be OK success (maybe you have an OK exit with equity but not life changing) over 4 years of service and maybe 1 or possibly 2 will be really nice. And if you're really lucky one will be beyond amazing.
Right but I think even with "Successful" exits your equity will most likely just get you back to level if you had instead spent the time at Google e.g.
Over a 25 year career, possibly. Especially the last 20 years as Google stock has performed so well!
Saying that, I've had some jackpots where there's no way Google compensation would have come close in the same window (couple million a year over a 4 or 5 years, for example). But other periods where it wasn't as good too.
Also, not everyone wants to (or can) work at Google. I personally enjoy building startups and everything that comes with it.