300K is on the lower end of salaries, esp. over 8 years. This is also just run-of-the-mill individual contributors that got in very late. Early employees, senior/leads/managers/directors/vp will make substantially more.

You're also assuming they did nothing with their earnings over those 8 years - when in reality most are invested in the markets which have killed it over the last decade.

I think people in tech are making a shitload more money then most realize.