I am pretty sure UBI will be at least tested at a large scale in our lifetime.
In the US, they can't even figure out universal healthcare, do you really think they are giving to go for UBI?
I am from EU, so I can see it happening here, or in some smaller countries. Here, you already sort-of have an UBI, where you get enough social benefits to live off if unemployed.
Huge numbers of desperate, armed, unemployed people have a way of focusing the will.