Phoenix has a thriving tech community? What?
I lived in Phoenix and I moved to San Francisco to find work precisely because of Phoenix's dismal tech industry. After my contract ended last year, I had three or four job opportunities in Phoenix that I had to turn down. There is no worse feeling in the world than turning down work when unemployed because those jobs would have been huge steps backwards in my career.
One was with a college where I'd be rewriting the same web form in PHP with some rudimentary javascript every day--no growth opportunities. One was with a custom automotive shop that hosted their website on phpBB and had the worst code imaginable as demonstrated to me on a programming test. Another was with a web design firm that listed the most extreme political candidates in the state as its clients. None of these jobs were accessible by transit, incidentally, and would have given me upwards of a 20 mile commute from downtown (the only place in the Phoenix area with a modicum of arts, culture, and entertainment options--and that's about 0.001% of what the Bay Area can offer).
IMHO, it's still 2006 in Phoenix's web dev industry, with a bunch of crappy PHP jobs and maybe five Ruby on Rails jobs postings a year. Companies that serve millions of users and are on the absolute cutting edge of technology simply do not exist in that town. I am certain that my job, writing enterprise social media management software in Ruby on Rails does not exist in the state at all.
Practically speaking, the access to venture capital, tech journalism, and labor in San Francisco and Silicon Valley is utterly unmatched in the nation.
Personally speaking, my quality of life, partially because of a 43% higher paycheck (before bonuses) than I'd ever make in Phoenix is unmatched. My rent might be three times as much, but I've more than made up for it in improvements to my social life, mental health, dating life, and about two dozen other factors. The funny thing about expensive places to live is that they're worth it. Your idea that people have a better lifestyle in Phoenix compared to San Francisco is an absolute Dunning Krueger--there are FAR more factors to one's quality of life than how big their house is.
When I talk to Californians about Arizona the only positive thing I heard was that somebody liked Sedona or Spring Training on vacation. The vast majority said Phoenix was too hot and racist and couldn't imagine living there for any reason. I wouldn't move back to Phoenix for a part time job that paid a half million a year.