Medicare for All has Been Around for Years

Below is a chart of the fraction of Democrats (including Independents who caucus with Democrats)  that sponsor or cosponsor "Medicare for All" (M4A) bills, including Senator Bernie Sanders' earlier versions under the title "American Health Security Act."  All of these would prohibit private health insurance (Ted Kennedy's "Medicare for All" bills are not included).

This shows that M4A has enjoyed significant support for a number of years.  What is recent is for people to recognize what the bills actually say.