How much rental vacancy is needed for there to be enough space for people to move around? 3-5%? Too low and you have gridlock.
https://www.census.gov/housing/hvs/files/currenthvspress.pdf
Home vacancy rates are currently at about 0.9%(!!)[2]
These are both very low. In home vacancies it's probably the lowest the US has ever seen, and in rental rates it's almost the lowest, and many metropolitan areas are probably experiencing the lowest rate they've ever seen.
Supply is the problem. Almost every other comment I see on this topic seems to suggest that the issue is something else, but this is all really simple economics. Supply in the places where people want to live is very low, demand is very high (and possibly higher than ever due to pandemic pressures), prices go up up up until the supply-demand curve settles down.
I'm not afraid to use the government to try create justice in housing, but the fact is that the only thing that really matters at scale today is SUPPLY. If we get more supply in the places people actually want to live, prices will go down. The fastest and cheapest (and probably only) way a government can make this happen at the scale needed is by making construction of (or conversion to) new dwellings much cheaper. If you are proposing policies that don't do this, I think the best outcome is nothing and the likely outcome is an even more messed up market that will inevitably privilege the rich over the poor.
As far as commoditizing housing, I just don't think it's a problem (and probably not very viable either) so long as there is enough housing supply. Anyone who thinks the residential-real-estate party is never going to stop is out of their mind or trying to scam investors. The party will stop.
[1]https://www.census.gov/library/stories/2022/05/housing-vacan.... [2]https://fred.stlouisfed.org/series/USHVAC [3]https://ipropertymanagement.com/research/rental-vacancy-rate...