For one, the operational word is “experiments”. People on experimental UBI know it’s only temporary.

For another, they are never large scale. So you can have success stories about how people given a UBI reprieve were able to take a moment to get things together, get some training, and maybe be selective and find a good job, but it’s unfortunately not saying how it would scale. Unfortunately those great opportunities are likely sparse, and if entire cities could take that same benefit, you’d likely see a reset to a similar scenario as before UBI. That said it may be a much better simpler situation than means tested welfare, but the ubi amounts in the experiments are often less than welfare, so you’d not replace the system…

Then there’s the debate of how much UBI.

On top of everything else that’s been said, most people would want more than just whatever the UBI was even if that was enough to survive on. Most people do not want to just survive. Sure, you might get enough to live a very basic life without any frills if you didn’t work, but isn’t it better to guarantee those people homes and food rather than just let them die in the street?