What UHC proponents never honestly admit is that these headline figures require incredibly optimistic assumptions and also much more rationing of care than our current model. We spend a lot on healthcare because we consume a lot of services. To save money, you have to buy fewer services. Yes, you can squeeze providers a little bit ("Medicare-level payments to providers" -- which they will absolutely hate, by the way), and you get another little bit by disposing of insurance provider profit margins ("reduced administrative overhead"). But the vast majority is coming from rationing, which people hate. And it would also cost massively increased taxes on the middle class, which voters also hate.

"Fewer avoidable emergency department visits and hospitalizations" -- sheer optimism. "Less fraudulent billing" -- no reason to believe this would be true. There could be even more fraudulent billing! Medicare fraud has been a big problem, and solutions are largely reactionary.