A Google programmer blew off a $500k job offer because he is already making $3M

A typical Google engineer has several sources of compensation: a base salary, annual bonus, and stock.

The base salary is effectively a fixed value you know in advance. The annual bonus depends on performance, but you get guidance and can estimate it. The bonus is significant, but typically smaller than base salary.

However, the stock grants are wacky. You're granted stock which vests according to a schedule. After several years, the vesting schedule starts to grant more and more stock per unit time (you get new grants, old grants take a while before they vest, etc).

Finally, Google's stock has been increasing since 2008 (there was a big drop in early 2008). This makes stock grants lucrative in a way that scales very differently from typical base income or bonuses.

Likely true iff the majority of Google programmers live outside the US (and other rich countries).