I don't understand the obsession some people have with keeping your existing plan. Lots of people can't keep there plan under the current system. Insurance companies update their plans regularly. Sometimes they remove plans or exit markets entirely. An existing plan will get small changes over time. If Theseus has an insurance plan for 10 years and the insurance company makes changes every year can we still call it the original plan of Theseus?
If M4A plus supplemental insurance gives me about the same coverage I have now for a reduced total cost that sounds like a win to me. Even if it ends up costing me the same amount the net improvement from everyone having access to basic health care would still be a win.
Every policy is easy to enact if you just define away anybody who'd object to it. But, more importantly: it's unlikely that M4A by itself (let alone with the supplemental plan you'd likely end up with) would reduce your total cost!
If M4A plus supplemental insurance gives me about the same coverage I have now for a reduced total cost that sounds like a win to me. Even if it ends up costing me the same amount the net improvement from everyone having access to basic health care would still be a win.