Firstly, the UK isn't usually at the top of the highest rated healthcare systems so 1) we're probably not going to try to emulate their system and 2) we don't have to copy one countries and that's it. I don't know what you're trying to say here. The UK has a doctor providing care to more patients because it's smaller? I could see what you're saying if your claim is that the population density is higher so you aren't forced to spread services out geographically but this doesn't make any sense.
No, I'm not incorrect on point 2. Payroll taxes hit everyone.
Federal Income Tax is something that a non-negligible part of the population doesn't pay.
https://www.brookings.edu/blog/jobs/2012/04/06/the-truth-about-taxes-just-about-everyone-pays-them/
It would not amount to a 20-25% increase in taxes, I'm going to need to see some math on that. Bernie Sander's proposal was, I believe, a ~2% payroll tax on employees and a ~6% payroll tax on employers. This corresponded with a somewhat more progressive income tax structure as well. His plan was criticized for being too optimistic in its costs but nobody said "he's off by a factor of 5". Closest thing I could find in a pinch:
https://www.washingtonpost.com/blog...-bankrupt-america-to-the-tune-of-18-trillion/
Also worth noting is that while
taxes certainly will go up with a single payer system, overall expenditures towards healthcare would drop (in theory). Sure the
federal government would be paying more but we would no longer have insurance premiums, we'd have lower costs at the point of service, employers would no longer provide healthcare, and wages would rise because this benefit is no longer meaningful.