> I'm arguing about the feasibility of it in light of naive statements.
I have directly addressed your question with the fact that already a third of Americans are in a single payer system, and most of the world has a single payer or hybrid system.[1] It's naive to think we don't know how to do it, and that we can't learn something from other nations when we expand it.
If you don't think we're capable of achieving the same results as a bloc of nations that has twice our population and many more cultural differences between them, why? Low confidence in America as a whole? Math and science fundamentally change in different time zones? Nobody in America knows how to read German, Spanish, French, Japanese, Korean, Italian, Swedish, Norwegian, Dutch, Belgian, or English?
> If the answer was "Just expand Medicare", it probably would have been implemented already but the fact that it's not should tell you something: maybe it's not that easy.
There's an even simpler explanation: S.1129 was not passed.[2]
> So my question is not whether or not you think it's a good idea, my question is how do you get from the current state to your goal of a single payer system?
No, your question is, "How can I keep the conversation going pretending that I'll accept an answer?" So let's nip that, and you can answer the following question: what evidence would convince you it is feasible?
[1] https://en.wikipedia.org/wiki/List_of_countries_with_univers...
[2] https://www.congress.gov/bill/116th-congress/senate-bill/112...