Game theory, it’s in the interest of every landlord if prices go up a little, so the overwhelming majority will raise rent.
Fact is only so much stuff is made and only so much space exists and only so many people exist to make and build etc. Money is just an abstraction for allocating those resources. Broadly speaking the market would adjust and everything would remain the same for 95% of people. The HOPE of UBI advocates is that, after adjustments to prices, the UBI would have an impact on that last 5%.
The thing about real estate though, is that supply is inelastic. Your one landlord cannot just turn up production and pump out a million widgets of housing. They’ll sell out, fast. And you’re back to square one.
All the sophisticated (institutional) landlords modeled and realized that with higher prices and lower occupancy rates they still make more money, and they all use ONE company to set their price on each unit.