This isn't really true. Everything in the Bay Area is more expensive. A quick Numbeo search, I found that housing in SF is a little more than 2x as expensive

This isn't really true. Everything in the Bay Area is more expensive. A quick Numbeo search, I found that housing in SF is a little more than 2x as expensive as in Austin, so somewhere around the same ratio. Consumer prices, excluding rent, are 43% higher in SF than Austin. Even your chain restaurants are more pricey. Everyone has to pay rent, ya know?