>Then turn it into a tax and be done with it.

Democrats tried, they did not get 60 votes in the Senate between Jan 2009 and Jun 2009. What we have is because at least 41 other legislators, including all Republicans, decided not to offer the US public this option, and since then Democrats have had nowhere near the numbers to enact any further reaching legislation, except the No Surprises Act in 2021.

https://en.wikipedia.org/wiki/Public_health_insurance_option