This may be true. But there are also be factors that may cause people to increase their income. Perhaps the extra money lets them invest in education (everythin

This may be true. But there are also be factors that may cause people to increase their income. Perhaps the extra money lets them invest in education (everything from skills training to a university degree), relocate to somewhere with a better market for the skills they have, or start a business using the basic income as their bootstrapping fund. It's hard to say how things will balance out. That's why I'm in favour of some sort of systematic test of the concept.