I think a better word than "insane" is "unsustainable." A pet theory of mine is that if the median household salary in a given locality isn't enough to qualify for the median mortgage in the same locality, that locality has a problem. All of San Francisco has that problem and an increasing amount of the area around it does, too. I'm not sure when this will come home to roost, but I'd be surprised if it isn't within the next couple of years. (I also suspect the tolerance for spending three hours a day commuting between SF and the South Bay, even on private buses, will drop as the commuters age, but we'll see.)

There are still places which are considerably cheaper and even still accessible via regional transit like BART, but they're cheaper because they're not considered "interesting" neighborhoods. In another 6-12 months we may see a lot more people deciding the East Bay isn't so bad after all.