UBI would've been great before mass immigration. The cost of having everyone "work" is greater than paying UBI, and giving some people the chance to become great academics, entertainers, and artists or to create an entertaining project.
Jobs which are worthless are worse than no jobs, and the worse case scenario would be an improvement from the current system. In an ideal or even average implementation of the system almost everyone would have more time and money because it would cut a lot of inefficiencies out of the world.Working on the tl;dr, since I'm not reading this whole thing. UBI won't work because giving people money for nothing will incentivize them to blow it on worthless shit (namely gadgets/consooming/drugs). It will also be incredibly expensive and will fucking destroy the economy by devaluing the coin, especially when the people who already live on gibs will still get the extra money (so there is no way to at least save money on reducing government bloat).
Also the elites fucking love the idea. Like always the middle class will pay for this shit, while the rich will find a loophole to not pay a dime. The government is weaker, the middle class is weaker, and the rich and the corporations will be stronger than ever.
When your country has moved to needing to pay citizens because there are no more jobs, since the government chased away every employment option. The only real step is taking that government and putting its head on pikes and breaking the legs of the competition.