Although I get one of the biggest appeals to SF besides the flexibility is the large tech industry, but you'd be surprised how many meetups, companies and stuff you can get to because of the close proximity to two major metropolitan cities, and Irvine (believe it or not) is huge in tech but just business in general here.
I'm not saying "don't come here" (like many Coloradoans do). Just do your research.
That $350k number probably includes Denver and the surrounding area - the "under $500k" (like $450-499) number is more appropriate for closer to downtown.
Edit: According to Zillow you are correct http://www.zillow.com/denver-co/home-values/ http://www.zillow.com/seattle-wa/home-values/
The Denver Post says $400, but that's still not Seattle prices. http://www.denverpost.com/2016/06/03/denver-median-home-sold...
But SF is unique in that you have a major, cosmopolitan city that's relatively close to a wide variety of terrain and environments, from beaches to forest to mountains, etc. SF is a compromise like any other option, but if you love the outdoors, it's one that gives you a hell of a lot of flexibility while still enjoying the benefits of a large city. It's not Jackson Hole, where the mountains are right there, but no one expects it to be.