> I propose making all forms of price discrimination illegal in healthcare, i.e. uninsured and HSA patients cannot be charged more than health insurance companies.

As long as it's left generic so it goes both ways. Currently it's usually the uninsured patients who are charged less (since they're paying the whole thing out of pocket instead of having insurance cover most or all of it), not the insured patients.

I'm not comparing the bill uninsured patients pay to the bill insured patients pay. I'm comparing the bill hospitals charge uninsured patients to the bill hospitals charge insurance companies for insured patients.

Hospitals and clinics offer a preferential rate to insurance companies as a sort of volume discount because insurance companies with thousands of patients have a lot more negotiating power than any individual patient who is uninsured or using an HSA.

It got even worse once health insurance companies started negotiating contracts with favored nations clauses requiring hospitals to bill then ~10-30% less than patients paying out of pocket. It's an oligopoly, but on the demand side: an oligopsony.