The problem that most people have with M4A is that they envision it being implemented more or less as Medicare is now, just for everyone. That would maybe work, but it would better to overhaul the system to a true UHC, IMO.
Because Medicare sprang up in the already existing market that was ruled by employer/private insurance, it doesn't really work like it could. The big difference is that costs at the provider level aren't really controlled in a meaningful way. It's capitalism...charge as much as the market will bear.
The classic examples of picking some medical procedure in another country with UHC compared to the US. You could usually afford to fly to that other country, get a 2 week vacation, and still get your issue (broken arm, major surgery, etc) taken care of. A broken arm doesn't need to cost $6k like it does in the US. We need to get out of that mindset before any meaningful change can happen.
Costs need to be regulated (and we can use other countries for good guidelines) and eliminate so much of the current waste in the system. Something like 2/3 of medical expenses go to paperwork largely due to the non-standardized billing from all the private insurers.
