The housing market in Japan is very different, for better or worse. As a consequence of the fact that houses aren't seen as investments, people...don't invest in their houses. They don't make necessary repairs, so the next owner would rather knock it over and rebuild than risk living in a rotting deathtrap [1]. From a macroscopic level, this is an enormous waste, because society is investing all these resources just to tread water, instead of accumulating wealth and resources over generations.

[1] Raze, rebuild, repeat: why Japan knocks down its houses after 30 years: https://www.theguardian.com/cities/2017/nov/16/japan-reusabl...

It's cultural. Americans generally have lower savings rate (when compared to other nations) and a home is one place where 'investing' and spending can overlap in a fairly bespoke way compared to anything else you spend money on.

You can't live in a share of stock, though it may appreciate faster than a house. (You also generally speaking can't use leverage to purchase shares). But even if shares appreciate faster than homes, they don't feed into conspicuous consumption: and that matters to some segment of the population.

Nothing can be both affordable and a good investment. (If it is a good investment, then its value relative to other things increases. If the value relative to other things goes up, then it ceases to be affordable.) Housing programs were a short-term boost to the wealth of the people that could access house lending (see redlining and the impact on Black wealth) but ultimately encouraging private ownership _as primary savings vehicle_ is a failed economic policy, and as things are often the case, the only thing worse than this policy is possibly the repercussions of unwinding it.