Some of this may be correct but writing off administrative overhead as negligible is laughable.

Insurance companies spend a maximum of 80-85% of collected premiums on healthcare, and only because this is regulated by law, otherwise it would be even less.

On the other side hospitals, clinics and private practitioners all have dedicated departments and staff whose only job is to deal with billing and negotiations with insurance providers. That also costs a hell of a lot more than a couple percent.

So just adding up these two there's 15-30% of medical expenditure that isn't going towards actual care, just overhead. Recover this cost and the US will immediately fall in line with how much the rest of the developed world spends on healthcare, even with the high doctors salaries and drug costs.