In the early 20th century, both Canadians and U.S. citizens formed unions to push for better living/working conditions in their country.

The difference with regard to healthcare is that Canadians convinced their government to provide it, while U.S. citizens convinced their employers.

This was fine for most of the century in the U.S., but towards the end and more recently leading up to the passing of ACA, all but the most zealous unions were broken up and employers were providing healthcare less and less.

Unlike the industrial, early 20th century where conditions were horrible for almost the entire working class, we now have some people who are gainfully employed with healthcare and some who are not. Consolidating these two groups to agree on how to provide healthcare for everyone is difficult, because those who "got theirs" don't see it as a problem until they lose it.