Those are the outliers that so many of us are shooting for. I guess I think it would make sense to optimize equity plans for those cases, and cash for the chance those don’t happen.
In terms of when to move on — I generally left too soon! What I like to tell folks is you should not leave a job unless you feel like you have made an impact that you set out to do upon joining and can walk away proud of that impact *or* feel like the chance of achieving an impact is near zero given your role and opportunity (eg worse than when you started) and then you should look for something new. If you have made an impact, then you should weigh the chances to have a bigger impact elsewhere or better to double down on what you already have done. It is easier to get compounding impact on what you have done, so you would really need to find something stellar outside to switch to that.