What we need to do is de-incentivize the commodification of housing entirely. Really make it unprofitable to deal in homes while passing the risk for your "investment" on to the people you're exploiting.
I'm talking about an outright ban on all corporations, foreign and domestic, from owning single family homes — corporations need offices, not homes, and shell corporations and LLCs don't even need those. Give a one year grace period, then tax all rental income collected from single-family homes at 100%. Maybe fine them each year too until they shape up.
I'm talking about regulating rental prices on short-term rentals, and capping the annual income allowed from short-term rental units to a value indexed against minimum wage (or preferably the area's living wage, determined not by any level of government itself but by valid third party organizations).
I'm talking an annual federal tax on properties not occupied full time by the owner or their immediate blood relative. Parent, sibling, or child. Something insane, maybe 400-800% of the home's property tax. Multiply it exponentially for each hoarded home. Throw in an exception for a second home if it's far enough from the first (people who own cottages aren't the problem, and shouldn't be penalised). But only for the second home — nobody needs two or three or four "vacation homes".
That's how we force land-rich boomers out of the housing "market" and get homes into the hands of people who need them, who should have a right to stable housing, who are currently being blocked from the market by vampiric land leeches.