So again, can you please provide objective evidence for your assertions? Eg. "vast majority remains productive in some capacity." - I have no idea whether its true or not. Why should I trust you when you haven't provided any data to support that claim?
This is only true if the existing system does not keep on worsening. As the technology progresses human working hours has become more and more. How is this even fair when the whole point of technology is to make human life easier. So the Burden is on the people who want the current system not to change.
What if it is impossible to bring the proof before the change has been tried? There is essentially no test scenario which can replicate, accurately simulate and predict the behaviour of people when millions of them suddenly receive a UBI.
At least if one agrees with the claim I just made, then following your logic, the change could never happen, for the simple reason as advanced proof of the effects is impossible to provide. So you would simply never find out if the proposed system would be better or worse than the current one.
Having said that, I do think the article makes a point worth considering.
... big changes could never happen... FTFY!
Which is what we are seeing: non-trivial health care changes happened in 2010 after 1965 (45 year gap), needed massive majorities in Congress and incurred huge political backlash. i.e. a smaller step was possible only after all the stars perfectly aligned.