How so? The government could mandate health insurance, and provide a health care option for those who choose not to get it from somewhere else. If enforced, this would make health care (of some sort) universal to everyone.
> So the question isn’t inefficiency because both sides concede government is inefficient
I agree with you that this is a central weakness in John C's argument: Libertarians (like myself) spend a lot of time trying to convince others that the government is inefficient, when the argument can only be resolved by quantifying exactly _how_ inefficient it is, whether the costs override the benefits. This is a much harder proposition to prove, though I suspect that John C is right that the costs almost always are greater than the benefits.