if you have the funds to early exercise, chances are you're joining a company that isn't yet a rocketship. and of course at that stage you can't make the same comparison with what you'd get at FB because your strike price is probably in the pennies and you're getting some small % of the overall company.

Real world example: low to mid level engineers at Uber joining in 2014/2015 at this point have stock worth over $2m over 4 years if Uber successfully IPOs at $100b+. By that time, Uber was already at "scale", offering RSUs (options strike price would be so expensive that it would be a huge risk to exercise), and that $2m is almost definitely more than what you'd otherwise have received in the same amount of time working at Google or FB.