[munificent]

People are downvoting this, but I think you point to a real problem.

Yes, people are generally good and want to do meaningful things and contribute to society. But we're also lazy, selfish, and good at convincing ourselves to make short-term choices with poor long-term consequences.

I think with UBI, there would be a whole lot of couch potatoes. I don't think that's necessarily morally a bad thing, but if the ratio of couch potatoes to people producing economic activity that pays into the UBI fund is bad enough, it can make UBI simply economically unsustainable whether you think it's a moral good or not.

So there is a balance between:

A. Keeping UBI low enough to incentivize people to produce labor such that UBI is financial self-sustaining.

B. Keeping UBI high enough that people who do not work are not destitute.

I think fans of UBI have a tacit assumption that A is well above B, but I am not so certain.