its a bit more complex than that.

However when you join you are given a bunch of shares that are paid out every quarter.

The wage is tied explicitly to your level, the number of shares is a bit more flexible. dpeending on what area you work in, and how in demand your role was, your shares make up between 10and 70% of your take home wage.

Every year you get "refreshers", again calculated centrally by level. For example an "E5" (the lowest level of senior engineer) may get a refresher of $150k of shares at january prices. Your performance grade is then used as a multiplier (ie bad == 0, ok == .75 good == *1.0 etc etc etc)

so even if youre not that successful you can amass a large amount of shares.