I think it was Robert Reich who said something along lines of:
"It's interesting that rich need to be incentivized by profit, while poor need to be incentivized by existential threat of losing their job."
Unfortunately, your comment is exactly this line of thinking. But you're wrong - with UBI, people who want to get something will still have to pay somebody else to do it. That's why people will still work - because it will pay off.
Yes. One claimed advantage of UBI is precisely that it removes the disincentive to work found in many existing social programs. Under most UBI schemes I've seen, taking a job would never make you worse off economically. That is far from the case with most of the programs we have now.
Air is even more important than food, but (outside of a few science fiction stories) no one worries about people becoming lazy because air is free.
Anyway, I should point out, though, UBI would probably make higher middle class (the people who have job, but don't have to worry about unemployment) a little worse off - they would have to pay people having low-paying jobs a little more, because the existential threat is gone. That's a good thing, IMHO. Although it makes the GP comment a little more nonsensical - UBI is actually against the interest of the higher middle class professionals.
"It's interesting that rich need to be incentivized by profit, while poor need to be incentivized by existential threat of losing their job."
Unfortunately, your comment is exactly this line of thinking. But you're wrong - with UBI, people who want to get something will still have to pay somebody else to do it. That's why people will still work - because it will pay off.