Let's pretend some of these SF twitter employees have families. $4k in rent monthly, 4k in general living expenses (these are based off median figures available publicly) A bit over $96k in living costs.
Assuming that $200k in total comp includes about 25% in stock (based off publicly reported comp packages for twitter employees), and a combined state/federal 35% tax rate... They have no spare money to save without a second income with $97,500 in take home pay.