Presumably you have to pay income tax on base+rsu so shave off >50% from these figures if you live in California? Then rent can run you 35-50k a year or more in the bay, and then other expenses? So 600k a year can be more like <200k savings at the end of the day? Someone debunk this.
Taxes average 30-40% in CA/NY, lower in WA, which has no state income tax. You are probably thinking about marginal tax rate, not average. Mortgage and property tax in the Bay Area can actually be closer to $100k, but some are paying that on dual income. $600k becomes more like $350k after tax and housing. That's still an insane amount of disposable income, hence everyone buying Teslas.
It would actually be something like this:
Gross: $600k
Federal Tax: $142k
CA Tax: $45k
Net: $413k
Effective Tax Rate: 31%
Of course your savings rate depends on how much you spend, you could easily spend >$200k/yr, especially if you have a family and want to live near good schools or pay for private school.