There are many things that could be done along this line. You could forbid providers that accepts Medicare patients from charging anyone more than X times the Medicare amount. You could forbid any carrier that wants to participate in the program I suggested from paying any provider more than X times the Medicare amount. Lots of other variations I’m sure.
Unfortunately, Congress is bought and paid for by interest groups who threaten to support an opponent in your next primary if you don’t toe the line.