So healthcare is one of the areas of society where it makes the most economic sense (!) and 100% pragmatically to have a large public insurer that doesn't need to make profit.
And most countries in the world have it since like mid-20th century, but not US because "values".
Same for pensions, public infrastructure, education etc. In most cases obviously the system is not 100% public but a hybrid between public and private - whatever works.