I know lots of smart people who worked for at least 10 years in very intense startup environments and got essentially nothing out of it. Often, they have to fallback on a life of contract work for huge boring corporations.
Yes, it's not guaranteed by anything.
I also know of cases where founder alone ended up with billions and early employees got nothing.
I just see those startups as poorly executed who decided to kill their army after victory way home.
We should strive for execution where at least your comrades also win.