Home ownership in the immediate post-war era functioned as a form of forced savings. To the extent it was an investment it was more akin to a reverse bond than a stock bought on margin: you pay a fixed payment on a loan for 30 years and at the end you own a substantial asset. The focus on price appreciation is relatively new.

In California specifically this was driven by Prop 13 gutting the property tax system and removing the natural check that higher property taxes impose on homeowners engaging in the sort of anti-development cartelism that has run rampant in California in the last half-century.