If you applied that uniformly across the US, no one city or town would become hot spots for migration.
I don't think this is really a workable policy, however. Not even sure it'd be constitutional for the federal government to do this.
And public housing has a reputation for being lowest-common-denominator, poorly-built, and poorly-maintained. If you drive through the south of the Potrero Hill neighborhood in SF, you'll see a lot of public housing, and... frankly, it doesn't look particularly pleasant to live there. I'm sure there are much worse options, but the housing there doesn't look in great shape.
Vacant properties should be taxed at an increasing rate sufficient to force the owners hand to either lower rates (and realize the losses from the new valuation from their creditors) or liquidate the property. The proceeds of these taxes can go towards the building and maintenance of affordable housing in the district their collected from.
This should encourage liquidation of speculative properties in hot markets and allow those without capitol to compete against those living parasitically off of their "investments".
Obviously this isn't perfect, and I'm open to admitting it's a terrible plan. But can we at least try something FFS? So long as people are homeless and can't afford to buy homes near their jobs I don't think anyone is entitled to profiting off of renting property.
Also worth trying:
Eminent domain land and task the national guard or army engineers with building minimally viable affordable housing condos. Attach a jobs program to train the un/under-employed from the area and scale up to the size of the problem.
or
"Yeah my policy is toxic political poison that will ensure the defeat of any politician who runs on it outside SF and Manhattan but SO WHAT?"
In that case why have politicians at all?
You can advocate for Soviet style collectivization and liquidating all businesses in the US if you want but no one outside of SF is ever getting elected on it in our lifetime.
If you think taxing zombie landowners and forcing a more equitable evolution in the archaic property market is too extreme wait until you hear some other ideas like:
Nationwide rent and mortgage strikes
Renters unions
Actually collectizing housing by taking property, some people aren't even ashamed to say they'd be forceful about it if their positions continue to deteriorate.
We can keep debating solutions to these problems until the worst effected take matters into their own hands, and pay more to clean up the mess, or we can behave like rational humans and make sure that everyone has the basic necessities of life as a prophylactic against mob violence from those with nothing to lost but their miserable lives.
So please, take a stand and share with us what your solutions are and how you're so confident they're better than the ones I've mentioned. Casually calling ideas extreme and unserious without honest consideration is at minimum rude and at worse a disingenuous bad faith distraction from the merits of my statement.