Example from personal experience that is very lucky in startup land:
I'm an unwise jr, who gets a 25k (with 25k stock units) purchase price stock plan for a series A company valued @ 5m. 4 years later that same company has 200x in valuation to $1b and I get 5k more stock units as refereshers over 4 years 'since the value of the company has gone up so much'. The value of my stock is not 6 million, but 600k because of dilution. So even with this very positive case situation, I broke even +/- 100k or 200k compared to big tech co with promotions, but whats worse, I can't sell my stock. The company later dies and all of that stock is only sold for about $40k total in secondaries that happened before the last $1b valuation round.
Considering that is the good case, why would I work as an early employee at a startup? With capital being so abundant and being employee #1-5 at an angel startup, I might as well become a founder and start my own at that point, or join the obvious next big tech co, which was facebook back then.
We also only have so many years to go on startup expeditions, maybe 5 total before we are 50, or more if we are able to fail fast.