I don't understand why a software developer would live in San Francisco unless they are making at least $50k more than what they could be earning in a low-cost state such as Texas (well, $50k assumes someone new starting out, can live in a small place, don't have a family, can't live with family, etc...a lot of assumptions). Otherwise, cost of living is just too high. The only benefit to being there is that it's easy to get a new job in case you don't like your current job so people don't get locked in and can move around a lot. They also work for start-ups and hope to become millionaires once their company goes public.