I am sure you have seen a multitude of Berners assert something on the order of "The cheapest, most efficient, simplest, safest, most accessible way to go is Medicare for all." This is their opinion, but they seem to think it is a fact. But it's not even a factual opinion.
The World Health Organization tracks how well different systems of healthcare work. Canada which is the role model for Medicare for All, is ranked 30th. Not first, 30th. Above it are countries with mixed systems. Most are multi-payer and many are public/private hybrids. 
Bernie & Warren both say Medicare For All to suggest familiarity, but they are not advocating that we keep the Medicare we have today--and that's good because today's Medicare is inadequate. However, it is a huge transformation that risks far more than they pretend with the name
That kind of massive dislocation of a seventh of our economy is not necessary to achieve the health care we need, when we need it, at a cost we can afford. We can amend the ACA to approach as system similar to Japan (10th).
Consider the number 1 ranked France. It has a public health system and a supplemental private system through mutuelles that people buy into to cover what is not covered by the public system (sort of like a MediGap plan)
Italy, the second best in the world, is also a public-private mix with national health organized by region. If we went to such a system, we would organize by state.
So how to we get from here to there? By passing the public option and creating the exchanges state by state. The point of the public option is that people would naturally gravitate to it over time as it does not have the kind of overhead a private carrier would have.
It would require fixes to some of the language of the ACA to overcome court rulings that have hampered it. That is a thousand times easier to do than repeal the ACA, pass a completely new system, which will be challenged in courts where 1/4 of the judges were appointed by Trump
Medicare For All advocates seem to think it will exist in a world devoid of legal challenges while the majority of judges have been appointed by Republicans hostile to national health care. Ignoring the context of our courts is stupid.
It is disturbing and hilarious that if you google best health care system you get Legatum Institute which provides a bullet (not number) list of some of the best. Canada is first, but source is this WHO study so if you read to the bottom, Canada is 30th. Talk about misleading.
So, people who google best healthcare system in the world and just look at the little box of info at the top that doesn't require clicking and reading will go away thinking Canada is best, not 30th. Now that is some serious propaganda. If you click, you have to scroll a long way
before it's revealed that Canada is 30th, not at the top. You can go the article that Google uses for its easy answer and see them plump up Canada then scroll to the bottom for the real info
worldpopulationreview.com/countries/best…
worldpopulationreview.com/countries/best…
