Startups pay more in salary than non-tech non-finance companies do in total comp. Startups that are far enough along (pre-IPO Uber, Lyft, etc.) pay more than FAANG (the RSUs aren't liquid but you need to only wait a year or two).
Uber employees who joined in 2015 actually saw their RSUs decrease in value by the time the lockup ended in 2019. 4 years of working at a pre-IPO unicorn for negative growth.
That depends totally on the RSU package they got when they joined. Negative growth if the package was 50% higher than their previous or FAANG comp is still a net gain.
If it was 50% higher when they were hired, they still probably made less. All FAANG stocks climbed 100+% over the same timeframe. Amazon, 500%.
[Edit] But... I think you might have missed the point. The reason to join a pre-IPO company is to make far more money post-IPO when the stock rises. Joining Facebook in 2008 or Google in 2000 would be equivalents here, and those people became very, very wealthy on the day of the IPO due to this pop vs when they joined. Uber employees who joined 4 years before IPO had their stock drop instead.
Startups pay more in salary than non-tech non-finance companies do in total comp. Startups that are far enough along (pre-IPO Uber, Lyft, etc.) pay more than FAANG (the RSUs aren't liquid but you need to only wait a year or two).