Average income is $48k in the US. Increase income tax rate enough that somebody with average income nets at 0. So having them pay $18k more in taxes while receiving $18k in UBI seems feasible-ish, if barely. Having them pay $36k more in taxes puts the rate over 100%...
That's assuming this never results in a single job not getting done. For example, I'd stop working and just live on rents, some trading, how many would do the same?
This is a more general problem with UBI of course, they all depend on a global desire for every single individual to contribute to society. And here I am, I don't think more than 10% or so of people feel that need. Of course 50% just outright can't, due to being too young or too old.
And assuming you're figures are correct that would already drop $1500 to $750, which wouldn't cover rent at all.
Most people living on rents make above average income. They'd pay more in increased taxes than they'd get from UBI.
The $1500 was after taxes. If it wasn't, the average person would end up paying more in taxes than they receive in UBI. The goal was to net the average person to $0.
