The general point is valid, though, and often comes up in discussions about basic income or similar programs: if the hypothesis is that someone whose needs are

The general point is valid, though, and often comes up in discussions about basic income or similar programs: if the hypothesis is that someone whose needs are already met will refuse to work, then we can look at the existing population of people whose needs are already met as a way to verify the hypothesis. And we find the hypothesis is falsified by observation: some people who don't need to work don't work. Some people who don't need to work do work.