I think the only way it could work is when the rich actually CAN gain something for the goods flow going to the poor - that something can be a sum of "moral satisfaction from charity", "diminishing the chance of the poor majority revolting against the rich" and "statistically helping young poor geniuses (and creative people in general) to join the rich in the future".
For each rich person, the ratio of these will be different, but multiplied by a portion of their worth they are willing (or being forced) to give, will in the end define the total amount of UBI available.
My theory is that after automation is widespread, it won't really cost much to support the poorer portion of humanity, just as now there is a surplus of basic goods made of plastic (clothes, everyday items). In the future this will extend to food, shelter and connectivity.
But at the same time, the rich and poor will be further separated, as there will be no incentive for the rich to interact with the poor.