A big part of that is also the transfers between private insurance and Medicare, with health care providers accepting far lower rates for Medicare and then subs

A big part of that is also the transfers between private insurance and Medicare, with health care providers accepting far lower rates for Medicare and then subsidizing operations with the rates charged to private insurers. Hospital administration is pretty hellish. As is administering payments! Any functioning health care system is going to have a "band-aid" exactly ACA subsidies: make sure that those with the lowest incomes can still afford health care. Something in between Medicaid and the full cost. But as we rein in the costs and get healthcare to be a smaller fraction of GDP, the size of the band-aid can shrink.