This post is not intended to be anti single-payer health care or anti-Medicare, but it is intended to point out the immense complexity and bureaucracy that must accompany both.
Such plans do not simply pay all bills or provide everything for free as some advocates seem to imply. They must manage costs and thus manage the care they pay for (or not). This is true of every such system, even the ones held up as models for the US. Every single payer system in the world uses some forms of rationing or limits on care. If you expect otherwise, you will be disappointed.
Americans are pretty much used to any health care they want, when they want it. You can forget that!
Take a look at this story, but also remember that if Medicare didn’t have these restrictions and paid more of the bills, the trust would be bankrupt sooner and taxes and premiums to support the program would be higher.