I don't expect those popular areas to get cheap, but I'm speaking of the historic RE bull run that began in 2000 that saw the rate of increase vastly outstripping core inflation and wages. That was clearly a bubble, and RE is still ridiculously high as a multiple of median wages in many "hot" markets. LA, SF, Seattle, etc. are almost totally unaffordable to anyone below 1-2 standard deviations above the median income, which is crazy. SF Bay is by far the craziest at least among major cities, though I suspect there may be crazier small "boutique" markets around.

Bubbles are basically naturally occurring Ponzi schemes. They are not driven by fundamentals.