Slumlords require a limited supply of local housing to gain leverage. If people on UBI are free to move then slumlords are competing with each other, so the same market forces that keeps prices low everywhere else are in effect.
Some people on UBI would happily trade worse living conditions for more spending cash. But that freedom of choice is what enables efficient resource allocation.
"Slumlords require a limited supply of local housing to gain leverage. " Indeed - if you want to get rid of slumloards then how about getting government out of the way of new housing being created? San Francisco is the poster child for how utterly draconian zoning laws screw everyone, but lower income people disproportionately.
It wasn't "getting government out of the way." It was literally government working in tandem with the trade-union interests of finance, insurance, and real-estate to preserve the value of the "asset," real estate. The problem is BOTH the government AND allied private industry working AGAINST the interests of their constituents and clients. The correction here will be MASSIVE.
Some people on UBI would happily trade worse living conditions for more spending cash. But that freedom of choice is what enables efficient resource allocation.