Sell, then what? Another mortgage if they want to live in the area, or uprooting entirely. That 2 million dollar bay area house might have been a 20k house among 10-40k houses in the 1970s; today it's a 2 million dollar house among 2-10 million dollar houses, so at best you'd be doing a lateral move or downsizing into something grossly overpriced, or line up to become one of the 40 people trying to throw a cash offer somewhere in the stratosphere above list on some midwestern home.

It's a zero sum game unless you upzone and build more housing to meet the demand, because the population of this country has only gone up.