The US government already pays enough on healthcare to cover everyone. Total national healthcare costs are twice what a simpler single payer system as used in Britain would cost. The other half of the costs consists of profit margins and the huge amount of admin needed to divide up all costs into different categories and different providers, and people can't or don't pay, but mostly it's the amazingly complex administration. So the employers and employees pay half the cost of the US medical system, but the medical system would cost half as much if they didn't contribute and thereby cause a lot of additional costs. The H.E.C.K. is particularly onerous on lower paid employees, and makes production workers in other countries with more sensible healthcare systems a lot less expensive and can out-compete American workers on costs. The US healthcare system is a far more significant problem than than most people realize.
The US spends more on healthcare research and development every year than Britain pays for its NHS. We can cut the price in half right there if you want there to be no further improvements in medicine.
I understand a lot of medical research is funded through the NIH. The cost of US Health Insurance public and private I got consisted of the total of all the public funding through Medicare, Medicaid, Veterans Affairs, and a slew of other public funds, and an estimate of the total amount funded through employers, and employees. Some employer funding is funded is by the government, and there are subsidies to hospital for patients on sliding scales and the indigent. That's my very incomplete understanding. Altogether it is a lot of money and very complex. That it works at all is surprising, the people in it are mostly nothing short of superb.
But overall it does put companies at a disadvantage and incentivizes cutting staff numbers which in practice means moving some people off employer health care into unemployment or low paid employment. That is bad for the nation's economy, but it helps maintain company liquidity in a nation of very high healthcare costs. It hits at the low paid end and therefore incentivizes moving production work out of the country and puts US employees at a disadvantage, and therefore US manufacturing in total at a disadvantage.
It fits the overall plan of the very rich, expressed in Neoliberalism which is to cut employment costs even though it means moving a lot of the work and some of the revenue, out of the country. That's encapsulated in the US economic system which is Neoliberal, the liberal part applying to free trade, in other words buying from where ever is the lowest cost and best value. In practice than means dollars flow out of the country. And our weird healthcare system is designed to make that a lot worse. Single payer is a key stage to bootstrapping the economy.