I think you misunderstand how I'm aiming this. I would honestly rather explore more socialist approaches, or at least worker co-ops, because I feel that corporate capitalism carries within its nature its own destabilization through regulatory capture and social discord.

However, because I am speaking about the U.S. we're facing a hyper-moralized work culture, at least in part from its Protestant origins, where just being nice or generous to people because that's what humans deserve isn't enough. I am trying to make the argument from pragmatism and efficiency. Human motivation is also complicated and not everyone reacts to incentives uniformly. The current attempts to moralize through means testing of benefits hold a grain of truth but are mostly misguided and costly.

There are major perspective, educational, and ideological barriers to contend with. I'm not advocating means testing as other people in this post have been referring to. I am advocating making freely available, to anyone who needs it, shelter, food, or healthcare and having support from social workers at that point to guide them towards work, school, or other activities with the goal of actualizing their talents. Generally any sum given in UBI would face being whittled down to an (inaccurate) estimate for providing those same things anyways, unless the UBI was a direct dividend from the overall productivity of the country, or perhaps from a dedicated carbon tax.

Currently, social workers dealing with low socioeconomic status folks spend a huge amount of their time helping people find programs, fill out paperwork for benefits, and navigate intricate bureaucratic mazes that contain massive gaps in coverage. (A patchwork, as someone else commented) They could instead be spending that time helping people achieve a place in society, and correct multiple generations of neglect, ignorance, and trauma. Just handing money to people doesn't give them much agency by itself. They are still usually in a massive information asymmetry and in sick communities with addiction, trauma, crime, and ignorance. People need a sense of belonging and purpose to bring out their talents and motivation, and you have to raise up whole communities at once. Our current system alienates the hell out of people instead. The often depressing fates of lottery winners are exemplar of what happens when ordinary folks receive lots of money in isolation. Rich people also often do very stupid things, but their surrounding wealthy community and armies of assistants usually prevent that from spiraling into ruin. That's a key difference.

UBI without addressing those community factors is likely to end badly or not do nearly what people expect it to do, and will just stoke the status resentment that's already reaching critical mass here. Our current political situation was by and large affected by level of educational attainment and status resentment. You can't cut that Gordian Knot by just giving everyone an allowance and calling it done.

I would be interested in the research you're referring to though, and whether it applies specifically to the intergenerational poverty in the U.S. I wonder whether it's representative of all the communities it would affect. I don't doubt that some people would deal with free money in a positive way, especially people who have just fallen from the previous middle class and don't have layers and layers of barriers and trauma, but saying that just giving money, at country scale, to all poor communities would just fix their problems is a very idealistic claim to make. The socio part of socio-economic status exists for a reason: it's not just a distribution problem but the secondary effects of that compounded generationally with many other tricky cultural issues.