I'm not in favor of UBI at all and think the effects will be likely negative. But we're heading for a world in which the need for human labor in the vast majority of current tasks will be unnecessary and undesirable (the machines will do it 100x better than any human). There will be a lot of other jobs people do, but scarcity will have been so reduced that UBI will be economically feasable then, whereas it just isn't now.
