Just to address this from a non US standpoint. While I'm sympathetic toward both the desire to preserve the character and community of a neighbourhood and your antipathy towards rentiers - there absolutely is a housing crisis across Europe (and presumably in the US).

Part of the reason is the lack of social housing provision, with most EU governments reducing or all together abandoning their post war commitments to low cost housing.

Another reason is that, even in this era of remote work, the enormous majority of high paying jobs do require living in a large population centre.

Perhaps the largest reason is the financialisation of housing as an asset class by hedge and other vulture funds. Italy alone seems to have kept the housing crisis / shortage localised to wealthy cities - and it is the only wealthy EU country to have done so. Germany, Ireland, France etc, all have rents and housing costs far higher than their median citizens capacity to comfortably pay, even in very remote and economically depressed areas.

Italy by contrast charges high taxes on 2nd and 3rd properties, effectively blocking the aggregation of empty / underused housing stock. Which has resulted in rural areas and less populous cities being reasonably priced to live in. This is not the case anywhere else in Western Europe.