Also there is not the separation between provider and payer which results in providers angling for the most expensive treatments, only forced down by a payer who regards the patient as an unwanted liability. (This has been partially subverted in the British NHS by ill advised privatization.)
There's numerous examples in this article about how Medicare pays more reasonable prices for things than anything billed out to consumers.
Insurance companies often get the same sort of deals, but they certainly don't pass on the savings.
Yet the article says that the $800 billion a year the US government spends on Medicare is what's driving the federal deficit. So is Medicare part of the solution, or part of the problem?
Secondly, Medicare would be better funded if it was paid into like virtually every other single-payer system.
What's driving the deficit is taxes that are too low and military spending that's too high.