I have things to do later so can't wait..so I will answer my own question from the thread below. I think it is important that we all mean the same thing about "single payer" to be able to effectively debate.

Types of healthcare systems:

Single Payer: By definition this means that there is only ONE payment source for medical care, usually meaning the government. Doctors and hospitals may or may not be public employees. The patient (consumer) receives a service and the hospital/doctor bills a fee for that service based on a predetermined fee schedule. Traditionally, this means that there can be NO forms of payment for covered services outside of that single payer for any service covered by the single payer. But the hospitals and doctors could remain independent and in private practice fee for service. They were NOT required to be direct employees of the government. Canada had this system until about ten years ago when most provinces realized it just was not working..waiting times for many things such as cancer, cardiac and orthopedic services were causing horrible death rates among Canadians. They now allow payment outside of their system and patients can choose to either go through the public service or a private one. Germany was sort of a "single payer" system except that they never outlawed private payments, as was Australia. Because they always had a dual system in place, their public insurance was never as draconian as Canada's was (it had to compete with the private plans) and so the private systems in those countries focus more on convenience.

Medicare in the US is similar to the original Canadian single payer system..any doctor or patient who receives Medicare is banned by law from charging over the fee schedule for any services covered by Medicare. Supplemental insurance really is not supplemental at all..it only covers the 20% copays of Medicare. back in the days when Medicare reimbursed well, this was not an issue, but now that Medicare is in financial trouble and reimbursements have dropped, more services are being reimbursed BELOW the cost of providing them and so these options are being increasingly unavailable for people on Medicare because they are not allowed to pay on their own to receive them.

Mandatory Insurance: This is what Switzerland has. The law mandates you buy insurance, and you can buy it through an exchange. The difference between this and the ACA (I know they sound the same) is that the Swiss system is not so heavy handed in what each plan must cover, or in regulating how doctors must practice etc. Catastrophic plans are perfectly acceptable, for instance. The Swiss system is the most like private fee for service practice outside of the US, has some of the best health outcome rates..but is also the second most expensive per capita in the western world (the US is first).

British NHS: In the British NHS, most doctors are employed by "Hospital trusts". The government gives out block payments to each trust based on diagnosis and life covered, and the hospital trusts pay the doctors. These act as capitated payments..once the money ran out, it ran out. The central government provided a panel called the NICE to decide what therapies were considered "cost effective" enough to be offered through the system. Therapies that were not approved generally were not available in that trust. Different trusts had more money. If you were lucky enough to live within the geographical borders of a wealthy trust, you could get more things. Originally, this system forbid payments outside of the system as well, but Thatcher relaxed that rule substantially in the 80's, and now there is a flourishing network of private hospitals and clinics. The best doctors see their "public" patients in busy morning clinics, and see better paying "private" ones in the afternoons where they can spend more time with them. If you can afford it, you get your orthopedic procedures, cancer care and deliver your babies at the private hospitals. The closest thing to this anywhere else in the world is the VA system in the US.

The ACA is designed to bring us to THIS system. According to the ACA, payments to hospitals and doctors are designed to get us to form "accountable care organizations" that will eventually get block grants per diagnosis. When the money runs out it runs out. The federal government will run a panel called the IPAB to decide which treatments are "cost effective" and which will set the fees paid to the ACOs. The panel will be answerable only to the President (not Congress as our Medicare system is currently set up). Private fee for service will be "preserved" for those who choose it, but fees will be slashed to below the cost to deliver care in most cases under fee for service (this planned for around 2019 but the regulatory effects are starting now and ACOs are being formed). The ACA allows for people to pay completely outside of the system but then they and their doctors and hospitals may not be on government insurance at all. If either remain on government insurance, then they are bound to the reimbursement rates set by the IPAB even if they are paying cash. Someone can be "out" of the system or "in" but they can never be partly "in" and partly "out".

The systems in France and southern Europe are much more..complicated..because there is a LOT of "black market" payments and therapies going on. My friends in those countries laugh when they read reports about what they are supposedly paid in France.