Basic income proposals usually work something like this (numbers all made up, but close to those I've seen):
Each person gets something around the poverty level (say $10k -$15k per year). The taxes that are raised to pay for it would increase gradually based on income up so that it would be a wash for someone making $55k a year, and once you start making more than $75k a year, you start paying more.
If you look at those numbers anyone who decides they can live off of the basic income was unlikely to have been making enough to pay any federal income tax at all, much less enough to have been contributing to the extra UBI tax.
> where people with middle or high incomes are no better off, I wonder what they would think when suddenly large swathes of the population are able to live off the dole without busting their humps.
They will be living off the dole at the poverty level, not living middle class lifestyles.