I think it is challenging (but not impossible) to fail at stage 1. If you join any tech company that is already public and part of their compensation is incenti

I think it is challenging (but not impossible) to fail at stage 1. If you join any tech company that is already public and part of their compensation is incentive stock options and/or restricted stock which is refreshed annually, then 4+ years can deliver a pretty solid "boost" for you to do Stage 2. Stage 2 is harder of course, but 90% harder? A bunch of companies fail in the seed/series A stage. That can happen reasonably quickly (1 - 2 years), so stage 2 can take 3 - 5 years to catch the right one. And then stage 3 is kind of up to you're ability to hit the market at the right time. More difficult still, but not impossible.