San Francisco == expensive
San Francisco is one of the very most expensive places to live in the USofA. SF can proudly match prices with the most expensive european cities. A Big Mac, allegedly available for $0.55 somewhere, is twice as expensive in SF as in Redmond WA.
San Francisco is expensive because it is surrounded by water and other natural barriers. It's harder for SF to sprawl like most west-coast US cities have done. Housing is expensive, so wages are higher so housing is more expensive in a death spiral that is worse for punkers than it is for software engineers.
In SF, $100k buys you a software body with less than 5 years of experience, if you can find one at all.
And Geez, I'm sorry that after being ostracized in high school and slogging through six years of college, that I can get a six-figure job and afford to live right in town. If that's not ok with y'all, you can put down your xbox controller and re-take the SAT. Who knows, maybe you'll get to maintain my PC or run my test cases. Who's the punk now, huh?
All things considered, the 21st century is a pretty good time to be an engineer, and a rotten time to be practically anything else.