I agree that the argument that the threat of starvation and economic marginalization can be useful for motivating people to do something with their lives is unpersuasive now, if it ever was persuasive. I don't think people should face starvation, or even go without dental care, as a result of being lazy and unambitious, let alone mentally ill, disabled or physically handicapped. I am hopeful that this awareness is starting to become widespread, even if it will be a while (hundreds of years?) before something practical is done with it.
As the conditions during the industrial revolution show, Anglo-Saxon countries in general, and the US in particular, have an above average level of tolerance for the suffering of their own people. So I would not necessarily bet money on anything happening anytime soon in the US. It seems just as likely that we could let things get pretty dystopian. What is also worrisome is what will happen to political power with narrowing economic opportunity. You cannot even pretend to have a level playing field, with equal opportunity for all, when economic marginalization begins to affect a large number of young people, as well as a significant portion of the adult population, as structural changes gradually transform the present economy into something we can only guess at. With profits currently accruing to a small portion of the total population, politics will also go in an unknown direction, no doubt for the worse. If a basic income can help with a little of this, I think we should try some small experiments to test it out over several years. I'm for piecemeal, incremental change, carried out a little at a time. If the experiments go well, I would not mind if a number of present-day welfare programs, such as food stamps and workers' comp, were gradually consolidated into it. We should not let ideology get in the way of this kind of experiment. But at any rate economies are things that are supported and controlled by societies, and they are free to modify the rules however they want. The only thing limiting this beyond political will are any unintended consequences that follow, which is part of the reason you make changes in small batches rather than in one go. Eric