You're omitting a major factor in this. Jobs.

I moved from Chicago to the Bay Area and while I'm not a developer, the opportunities are still night and day in terms of the job options, the pay, benefits, etc.

A cheap mortgage on a nice house in a good neighborhood means squat if there are not a lot of job options, or only ones a long commute away.

Personally I think the best thing to help this is make remote work more viable for non developer professions that don't have as much demand or leverage. This would enable more people to live in affordable areas if getting another remote job were comparable to living in a market flush with jobs.