Four adjustments reduce national expenditure. Hospital and clinical fees are paid at Medicare reimbursement rates, which are below the rates paid by commercial insurers and above those paid by Medicaid. Pharmaceutical prices are reduced through international reference pricing, applying the 51% reduction achieved by benchmarking US prices to those paid in comparable high-income countries. Administrative overhead is reduced toward the level of the current Medicare program, reflecting simplification of billing and insurance functions under a single payer. Fraudulent billing is reduced, consistent with the experience of other single-payer transitions. A further reduction comes from averting emergency-department visits and hospitalizations that improved primary-care access would render unnecessary.

And none of this is going to happen. Let's count the problems.

1. A general pay cut for serviced providers
As is mentioned downthread, doctors/nurses/clinicians/staff aren't going to take that lying down. Some will rally, some will stay, some will go on strike but a good 25% or so of them will just...stop. Some will leave medicine altogether via early retirement or just quitting while others will set up on a secondary private market just as they are now. The government can't outlaw it no matter how hard they try.

2. Emergency room visits
Many people regard the ER as their first line of defense. Are ERs going to start turning people away? Of course not.

3. With staff reductions, comes scarcity
With the quarter of doctors/nurses/clinicians/staff choosing to not participate any longer, the burden of providing care for the country falls on the rest. Wait times will increase. Equipment that used to be top of the line won't be as it ages out and there's no money to replace or upgrade it.

And more.

Oh, and medicare fraud is rampant in our current system. It'll be far worse in any kind of socialized setup.