If private insurance companies are lobbying to prevent Medicare for All because they’d lose their business, then make them the claims processors. Like, the government pays the bill, but the carrier process the claim as a contractor to the government. That way they can still be publicly trades and still keep their profit margin, and people still get guaranteed healthcare. They’d even be able to keep what they’ve killed in previous profit, and they’d not have to be the source of funds for actual claims.

Since there are a few companies, maybe we could even use a regional distribution of the populace for who has which card on their wallet. So maybe the east coast has Blue Cross Blue Shield, the west coast has Aetna, and the central states have Kaiser?

This way everyone wins: heal insurance keeps in business and still makes money; the people have healthcare; and the government improves the lives of its population, has fewer bankruptcies, and can tax the revenue of its contactors like they do with their current contractors.