All a single payor needs to be is a payor. Doctors still work free of control. The market still works as it did before. And it can be two tier, in which those who can afford more can have more. And taking form tax dollars should be less expensive than unmanged price gouging done by hospitals that charge us all more because they treat people who can't pay.
But, let's define first:
Single-payer systems may contract for healthcare services from private organizations (as is the case in Canada) or may own and employ healthcare resources and personnel (as is the case in the United Kingdom). The term single-payer thus
only describes the funding mechanism—referring to health care being paid for by a single public body from a single fund—and does not specify the type of delivery, or for whom doctors work. Although the fund holder is usually the government, some forms of single-payer employ a public-private system.
Single-payer health care - Wikipedia, the free encyclopedia
The problem:
The reason we spend more and get less than the rest of the world is because we have a patchwork system of for-profit payers. Private insurers necessarily waste health dollars on things that have nothing to do with care: overhead, underwriting, billing, sales and marketing departments as well as huge profits and exorbitant executive pay. Doctors and hospitals must maintain costly administrative staffs to deal with the bureaucracy. Combined, this needless administration consumes one-third (31 percent) of Americans’ health dollars.
Single-payer financing is the only way to recapture this wasted money. The potential savings on paperwork, more than $350 billion per year, are enough to provide comprehensive coverage to everyone without paying any more than we already do.
Single-Payer National Health Insurance | Physicians for a National Health Program