It is more than you think.

According to data reported by the PEW Trust and originally gathered by CoreLogic, as of 2022, investment companies own about one fourth of all single-family homes. Last year, investor purchases accounted for 22% of American homes sold.

https://www.billtrack50.com/blog/investment-firms-and-home-buying/#:~:text=According to data reported by,-2021%2C why is this%3F

15 percent of the market is big enough to matter. https://slate.com/business/2021/06/blackrock-invitation-houses-investment-firms-real-estate.html

Yeah that’s the one I was referring to in response to OP, but measure it by whichever indicator you want (federal unemployment numbers, jobs growth, help wanted listing, increasing pay rates, union contract negotiation outcomes). ‘Unemployment’ (nor underemployment, nor labor participation) is not currently indicative as the causation for the housing affordability problem.

There are faster and more affordable solutions than “build more housing” or trying to convert commercially zoned property into residential and all the retrofitting that entails. Also, unemployment is at historic lows right now. You are right, though, homelessness is an affordability issue, and housing prices going up over 50% in the last 5 years (and 100% in the last 15) has more to do with it than anything else. Housing is being bought up by massive investment firms like Blackrock, creating scarcity in the market and thus driving up housing costs. These firms have long term aspirations to create a culture of renters, adding to our subscription-based economy and eliminating home ownership which has historically been the pathway to wealth for normal people. Governments could easily step in to address the issue by raising taxes on any entity’s 5th, 6th, 200th, etc residential property and make hoarding homes a bad investment. Those properties would be dumped like any other losing stock on a spreadsheet, and you could use the windfall from those taxes to create affordable financing for normal people’s first or even second homes. Unfortunately, at least in the US, the government officials in charge of making such a decision are financed by the very institutions profiting from the status quo.