Chatted with some early-stage-then-IPO-ed engineers yesterday, I asked "aren't your company IPO-ed and you should have retired?", the answer is, after multiple dilutions in rounds of fund raises, his options ended up worth just a few thousands, not useful at all. There is no way the startup you have been working for will keep your interest a priority, and you never know if your share will reach zero in the process of…
I think the main advantage of working at a startup is when you're relatively young and inexperienced - you're being compensated in the experience and accelerated job titles that you can then leverage to ramp up your career by joining other companies or starting your own. Getting an exit is a cherry on top.
The opposite can be true, when IC's at startups who have not truly learned their craft jump to management too early.