I have a somewhat sinister view of this. In my opinion, it would play out exactly how you described, and when it did, proponents of UBI would demand control over private sector pricing in order to stabilize. And since you can't just "undo" large scale UBI, government control over private sectors would have to be given, or the ratcheting up of costs and UBI would continue indefinitely. UBI is a foot in the door of more government control over life and business.