Northern CA price has always been a level higher than most other places in the US, yet decade after decade, it was able to defy logic and keep on rising. That proves to me that affordability is not automatically a regulating valve. Bay area's price has more to do with limited supply and high demand. Blame it to eco-friendly zoning law limitation. Of course, I am not saying that affordability has no effect, it has, but it's not a major determining factor.