For sure we want to understand the differences between Medicare plans, because it is key in the abillity to get the healthcare we need at Mayo Clinic amd other institutions.
It is not a big jump to arrive at "Medicare for all" in this discussion since people also discuss their "before Medicare" plans. I look at these discusisons through the lens of my background (degree in Economics, worked in Corporate America, many years of researching business and industries) ...so my "diagnosis" is based on assessment of numbers.
In strategic planning we first set goals/objectives, then study solutions and decide which one provides the most. So if our objective is affordable quality healthcare for all, we have to look at the numbers - outcomes and costs. Even 20+ years ago there were several studies showing how the US healthcare system is twice as high as Switzerland (the second highest) with no better outcomes. I also recall a study that asked nurses if they would go to a not-for-profit or profit hospital and they said "not-for-profit" I suspect the reason being that the NFP hospital does not have to cut corners to meet profit objectives.
Medicare administration is more cost effective than private health insurance because it does not have the sales and marketing expenses, it does not have to renegotiate with many providers each year, etc. And it has a uniform coding system...providers also have more costs because they need to hire people to process all kinds of different insurance claims. Our additional issue in the US is not having enough doctors!!!!