@SW-User I perhaps think that Americans want healthcare that is affordable and provides for everyone.
The point I'm making is about question framing. If you say to people that they could lose what they have and what they are used to, then yes you will get reticence. Change is uncomfortable, especially if you have something to lose. If you say that 'Medicare for all' is a good system, then people also agree. There is a contradiction based on what question you ask.
https://thehill.com/hilltv/what-americas-thinking/412545-70-percent-of-americans-support-medicare-for-all-health-care
If you ask British people whether the Government should 'control' all healthcare, it would maybe get 40% disagreeing but 85% of Brits support the NHS, with only about 8% against.