the biggest issue is why would corporations willingly act as a working class life support and loose profits employing large amounts of people a specially in a country like the us where they have a very large amount influence and control over the government. Also purely government based ubi is actually a popular idea with some billionaires in the us like Elon Musk, Richard Branson,Mark Zuckerberg. So in a post laborer highly automated/ai dominated economy a more likely scenario is that the government recycles ubi through taxes in order to artificially create consumers and to stimulate the economy.