So, we have evidence of much smaller ambitions not working out, and you claim it says nothing about much larger ambitions, and yet you don't have any answers. Interesting how all of the UBI discussions end this way.
You're right on most points, so let me justify why I believe it's worth trying.
First, the possibility space of politics/economy is enormous. Presuming European countries are the ones you're talking to which couldn't bear this year's economical help, that's a useful data point, but EU countries share a lot in common: developed, industrialized, capitalist, democratic, old society, efficient etc. That by itself doesn't exhaust all the possible configurations. One could imagine countries that retain the same desirable or unavoidable properties (democracy, old age), but differs significantly in others (simple tax laws?).
Until we determine whether implementing UBI would work from all reasonably reachable configurations, it's still worth evaluating.
There have been semi-successful UBI-like ambitions IMO, when we look at the idea of "bullshit jobs". While they exist in the West, the most interesting example is Soviet countries, where citizens were given the most pointless jobs, which would give them enough money to survive. Perhaps it's not the most successful thing ever, but it's worth noting this didn't cause an immediate collapse of the system.
Treating coronavirus help as a data point is also dangerous. The results are confounded because of how the world economy was affected by the lockdowns.