Awesome post!
I agree that a form of universal basic income will be essential in the future to maintain some stability. This topic fascinates me and I am lucky enough to have done a couple university projects on it. I have some responses to the problems you mention for basic income projects moving forward.
First, while I agree that these sorts of 'hand-outs would be difficult to introduce to the American public, there's a case to be made that conservative and/or republican voters may like it. Some of the literature on UBIs or Guaranteed Annual Incomes (GAI) suggests removing the welfare state in its entirety and just having a UBI. Removing the bureaucracy reduces cost, and efficiency is increased by providing funding to those that need it quicker, and indiscriminately. It would actually be better than welfare because (at least in the Canadian welfare system) you cannot have any substantial assets while on welfare and you cannot supplement your income. Most cost effective UBIs would be scaled with your wage. You could get rid of social security, disability, etc, and just have a UBI that covers those anyways (and maybe extra income as a result of certain conditions). - - - But ya, it's a leap. Ontario and Finland are piloting basic income projects right now. These are the trailblazers in this policy arena.
For your second problem, I agree, funding is a difficult thing to think about. Jurisdictions will each have to sort it out themselves. These programs will not be cheap, but costs can be reduced through the streamlining of the bureaucracy.
For your third point on lacking purpose in life, I understand the intuition with that problem, however, I've discovered in some literature on Canadian transfer programs and through other sources (https://www.psychologytoday.com/blog/hidden-motives/201510/the-myth-welfare-dependency) that dependency is a statistical myth and that when given the chance to better themselves, most people do that. I know more money for me can easily translate to more time spend on things I would rather be doing. More money for me means I can dedicate more time to making music, or spend more time with important people, or learn a new skill, etc, etc. Granted, some people may waste it, but I think there is a hidden potential that can be unlocked in society when you give everyone the means to participate.