The perspective of MMT is that government can and should tax out money at a rate that keeps the economy from inflating beyond the scope of our control, and inject it at a rate that sustains the velocity of capital. Making this perspective the dominant one in discourse, however, would require a lot more public trust in government before people got comfortable with the idea of governments taxing us for our benefit.
The NPV of that dilution would be enormous, unless the economic value being created is very close to $1000/mo (or higher).
I'm perplexed by how often people assume that spending will only increase with the introduction of UBI, when there are many existing pathways for capital to travel that will become obsolete when UBI is enacted, and can be diverted to funding UBI instead.
This is a good point. Money maps to stuff and services. But there is ample surplus production (and unused capacity) in our economy.
Every year 40bn+ pounds of food is wasted at the retail level (on top of all the waste that happens before retail in production), while ~11% of the American population is food insecure.
Nearly every clothing company — H&M, Nike, Burberry, Eddie Bauer, and so on — destroys billions of dollars of unsold clothing every year in order to preserve their brand.
We have material abundance thanks to highly optimised mechanisation and more recently automation in agriculture and manufacturing. UBI can allow the poorest parts of society access the surplus that we would otherwise destroy.
Having an income (via UBI or some other mechanism) would help the poor, that is true (minus the caveat above about economic upheaval). Assuming that said income will reduce economic waste is not at all evident.
However, a higher velocity of capital without commensurate economic value being created ~= massive inflation.
This is a potential risk for UBI, and one that small-scale studies do not cover. Ideally, the additional economic value would be greater than the face value of the capital transferred every year, but there is no guarantee that is correct (nor is there any reason they should even be on the same order of magnitude).
Implementing UBI on a national scale would be a grand experiment. Most grand experiments tend to fail with massive upheaval. I think for UBI to be adopted, you would need a plausible incremental strategy with a lot of safety checks.