Think auction rather than static supply/demand curves. If we both used to have $500/month for shelter, and our bids settle into some stable relationship based on personal preferences, if UBI comes in and now we both have $1000/month for shelter, we can now outbid someone else who stubbornly insists that UBI shouldn't change the price. The stubborn person can either drop their stubborness and bid higher, or see themselves outbid and be forced to take something they prefer less now. The stable outcome is that the money goes to the landowners in this incredibly limited and isolated model, which I am using only to illustrate the point in a simple way.

In a less simple way, there are many people, including me, who rather believe that making it easy to get money for college is the root cause of colleges getting more expensive. Having been back to my own alma mater about a year ago and seeing the unbelievably glorious meal hall they have now, which is more accurately described as a meal mall, it is abundantly clear that they have more money than they know what to do with and are spending wildly on things that have little to do with education. They're caught in their own trap; since the money is free to the students (at least for now), the university is forced to compete to be ever nicer themselves. Nobody has the power to decide to just go to a cheaper university because they'll get outcompeted by people anomalously flush with "free money". So college prices spiral ever upwards and the market mechanisms can't do much about it, because we broke the market by giving everybody "free" money, or more accurately, money whose costs were deferred beyond most people's ability to think about the future.

One of the reasons I stand against UBI is that the same thing will happen. The UBI will come out, but time doesn't freeze. The UBI will then affect the economy, and people won't quite get what they wanted out it as capital owners figure out how to extract the extra funds. And the politicians will be falling over themselves to be the ones who get the credit for raising it; who would ever be re-elected who lowers the UBI? UBI takes a "free benefit" death spiral we're arguably already on and throws it into high gear, and I can't see how we'd ever escape from it short of outright collapse. Nobody will ever vote against the free money. It creates a society where the short-term incentives are always in favor of more free money, even as the long-term looms ever more obviously in everybody's face, which would actually just make the short term "get what I can while the getting's good" problem even worse. It's a catastrophically broken way to set up incentives in a society.