If you by moving the goalpost mean I'm not that interested in the actual size of an UBI, then yes that is probably fair. The point of my argument is exactly that an UBI does not need to be conceptualized from the perspective of needs but rather from the perspective of rights. As such I do agree that the math may not balance out to an amount that is actually livable. Which I think is a fine outcome.
The point of my source was not so much the economic argument, which, after all, talks about a reality several hundred years ago. Perhaps I should have linked to https://en.wikipedia.org/wiki/Geolibertarianism instead, to focus on the moral side of it.
I do think however that a modern take, especially if it turns out that recent AI developments will have sizable impact on the demand for human labor, could very well turn out to result in a dividend that is actually livable. Paine talks about land, but we should really consider all commons: Land, carbon emission rights, patents, copyright, trademark protections, electromagnetic spectrum, ip4 address space, dns names, the list can be made pretty extensive.
Perhaps it should end there. We could establish the idea of cooperatively owned legal entities representing various commons. These entities can collect rent in exchange for allocating parts of the commons to private use. I have a feeling it would make sense to take it a step further though, even if the details are probably over my head at the moment. It's already the case that pension funds function as a cooperative ownership of a part of all capital assets. And then there is home ownership and its connection to loans and wages. There probably will need to be some creative restructuring of this situation.