The utopia vision as I understand it behind UBI is that automation takes care of most / all of the work people don't want to do.
I think the biggest challenge to this utopia vision (assuming automation gets to this point) is more that, frankly, labor is not wealth. Land is land for instance regardless of what is automated or not. Rent seeking for various things is rather common, most of which automation will not touch. I can envision strong resistance to any sort of UBI scheme from this group (some of this group frankly seem to not even care for our current safety nets now).
Before we go through a true "post work" phase, we'll probably go through a phase where service oriented jobs are the norm -- this is also harder to automate away completely, although probably not near impossible like tackling assets and rent-seeking. The main problem here is that this side of the workforce is currently rather undervalued IMHO. So if one wants improvements in the world of work, I personally think putting more efforts here would be better vs. banking on UBI.
Or, with enough automation, the world would be making leaps of progress in a variety of areas of human interest, because everybody is pursuing their true interests.
The idea being that we automate, design away or do without as much as possible of the scutwork and pay the remainder handsomely. Then people can do the things they like - which may well be highly useful, they just aren't what capitalism will pay for.
