That poll asserts specific criteria which are incomplete and possibly untrue. For example, there’s no mention that healthcare expenditure would actually decrease. It’s unclear whether wait times would increase. It’s also unclear whether a tax increase would actually be necessary because Medicare for all may actually be a deflationary event.
Yeah, of course the industry will propagandize with lie after lie. That doesn’t mean we should abandon the truth, and most Americans support the proposition when the relevant context is provided.
Social security is still around after all these years because it’s a UNIVERSAL program. It’s untouchable. Programs like welfare are not, and therefore are easy to demonize and defund. I don’t think Medicare for all is a “panacea”, but it has the potential to become a staple of the American system in the long run in a way I think the ACA does not (in addition to being a superior mode anyway).