The argument of whether people should pay for medicine is more nuanced when you realize that even when you do not gain direct benefits from these changes, you are benefiting.
Everyone, even if you don't own a car, benefits from roads and highways.
Everyone benefits from hospitals even if they are a highlander and will never get sick.
In fact it is economically devastating for a town, for example, to have its hospital shut down. Typically a town will be abandoned, which has happened before as Hospitals move for richer pastures.
I see the largest hurdle dealing with the employment loss should we switch.
The HUGE issue is just how much different of a situation the US is in then any other country that developed a universal healthcare system where it tended to increase the average pay and improve quality of care.
The US health system is extremely overbloated and going to universal would very likely lead to loss of wages across the board (and doctors are already typically overworked regardless of their pay).
It would be chaos... the US isn't going to get Universal Healthcare unless they absolutely want it IMO.
The other Big problem is that the USA is so anti-tax that Universal Healthcare in the USA would probably be similar to education... On the forefront of budget cuts whenever a politician needs to win points with the public. I can ENTIRELY see the USA tanking their own dang healthcare system.
Goodness now that is an argument: "The USA isn't mature enough for Universal Healthcare"