Glassdoor is incredibly outdated and inaccurate. Levels.fyi has much more accurate data. It is still true that only experienced engineers at a handful of top companies and decacorns tend to earn these high levels of compensation, but Glassdoor makes it seem rarer than it is.

The Netflix data for example is just flat out wrong. It only hires experienced engineers, and pays all cash salaries in excess of 300k to all of them.