And we have a very different population. Obesity is only the most obvious example. And no, healthcare doesn't address obesity, even if your argument requires that it do so.
And we spend more on end-of-life. Unless govt death panels are going to be more frugal than private ones, that cost-differential will persist.
And we pay for a huge fraction of the world's drug development. Are you planning to cut back there?
Well over $150B of existing medicare/medicaid spending is fraudulent, which is significantly more than the "excess overhead and profits" of private insurance. Will that go up or down?