I've been here for nearly a decade now. I know a fair number of people who have become genuinely rich (i.e. have fuck-you money in the bank), and people who are theoretically rich on paper.

With only a few exceptions, the genuinely rich people were either founders, long-time insiders at public companies (i.e. Google, Facebook, etc.), or (very rarely) early employees at smaller companies that had an exit (as in, employee numbers lower than 5).

Of the people I know who are currently theoretically rich, most are tied to "unicorns", because they can't sell their insider shares. Maybe these people will end up actually rich, maybe they won't.

But most of the people I know who match the profile you describe (i.e. worked at a few startups as a not-super-early employee, of which some succeeded), are doing okay, but are nowhere near retirement, and certainly nowhere near fuck-you levels of wealth. The expected value of the lottery seems to be something like a few years of market-rate salary at a big company.

What you're seeing in the bay area is the legacy of decades of this kind of wealth accumulation. Millions of people, taking 50+ years worth of chances, over a series of successive economic bubbles. Said another way: you're underestimating the denominator on the probability.