On the other hand, if you spend your early career as a researcher making five digits a year in the Midwest, then move to SV in middle age to increase your earnings, you probably won’t ever catch up and be able to live very comfortably given the cost of housing.
This is just a possible counterpoint, learned the hard way, to the common advice to “pursue your passion.” My advice to those who have the option: make some money first, then pursue your passion.
No, it's a lot for 4-5 years anywhere. This is on top of a pretty decent salary. For most working folk, putting this much aside in cash-equivalent over entire career is hard.
GP is talking about going from a high base salary to decent base salary, while using the extra comp (estimated here at approx 1mm) to smooth the impact of the drop in base. This is very manageable.