Any true single payer system is going to either impose cost controls, or see costs spiral hilarious out of control. This was part of the politics around Obamacare “death panels”, a political attempt to scare Americans to the simple reality that part of controlling healthcare costs is making decisions about where money and resources should not be spent.
Again, I’ve made note that I do not believe any dramatic, “flip the switch” moment from moving America from a private insurance based system to a single payer system will ever occur, so we’re getting into what I consider a hypothetical scenario. But in such a hypothetical scenario you would immediately see major pressure on all the providers to cut costs in a huge number of areas. I don’t even know how much of the cuts, % wise, would be in salary, but it’s likely some cuts would happen there–and salary is possibly the easiest to hypothesize about because of how straightforward it is to find the data there.
There is no real equivalent in the NHS for example of someone who is “CEO” of a hospital making 7 figures. There’s various ranks of hospital administrators who I think max out at less than USD $100,000/yr. The average U.S. specialist makes $223,000 more than their British counterpart, but holistic cost savings are a lot more than just cutting doctor salaries. The way patients are treated would have to change. The willingness to perform surgeries that probably aren’t medically necessary would go down, the classification of procedures as “medically necessary” would probably become much more rigorous, with more things being considered cosmetic or non-required at least, which in many single payer systems the system will not pay for routinely. There would likely be some increase in waiting times, as you would build out less testing machines and surgical centers to save costs etc etc. It’s really systemic the differences between how the U.S. runs its healthcare system versus other OECD countries, it isn’t as simple as just cutting wages.