if the salary you are getting sufficient, then they are taking a lot more risk than you are. most startups fail, as long as you are getting paid an amount that is sufficient for goals and are working on what you want to work on, you are taking on minimal risk. And most startups that do well, the employees do also do well (not necessarily as well, but they also took on less risk).

A startup that sells for 250 million after raising 300 million, did not do well.

A startup that basically went bankrupt and had to be recapitalized after you left, did not do well.