You answered your own question. If both landlords and health insurers (and etc) jack up their fees by the exact amount of the UBI, then where does the money come from? People only get one UBI, they can't double spend it to both rents and health insurance, can they? So at worst, the total amount of increase in cost of living can't be more than the UBI. But landlords and other people looking forward to cashing in on the money have to compete with each other, which keeps prices down. Eventually more buildings will be built to match the increased demand.
I was most certainly not implying landlords are keeping rents down to keep them affordable. Quite the contrary, rents in most major cities are well ABOVE what any sane
It's called competition.
This OP implies that landlords, etc, are holding prices down to keep housing affordable or something. Of course not. They're charging as much as they can, given that particular market and what they're offering.
They're still selling a product, to customers. If those customers are less desperate in the first place, they'll also be less willing to throw their entire income at class warfare's carbetbaggers.
Unless all the landlords collude, which i do think already happens, as rents are already above what any rational analysis would conclude the "market" can bear.
Same with healthcare.
Depends on how you define "collude". They do drive rents slowly up over time, using each other's rental increases as justification.