The salaries here are higher, but the housing prices are much, much higher. I live in Redwood City, which is a decent-but-not-amazing part of the Bay Area. A 1500-sq ft home is about $1.7m here. In Palo Alto, it would be closer to $2.5m-$3m. In a place like Portland, that same home would be $400k. The problem is that salaries here are 100% higher, but house prices are 300%-600% higher. And housing is most people's biggest expense. It's very tempting to move to a place like Portland, and either take a lower paying job, work remotely for an SF job, or even fly in for an SF job for a few days every week.
All of this feels completely untenable and unsustainable, and yet it sustains because there are enough affluent people that want to live here that their demand outstrips supply, and local city governments are criminally conservative when it comes to building more housing.