Earlier quoted context omitted.
Trivial inter-state mobility is a big obstacle for states doing grand social programs individually. If a state provided universal healthcare for residents, it'd quickly be overwhelmed with "hard cases" from other states where coverage is a problem. Which would drive up costs, and taxes, and drive productive/healthy people out. See the current inter-state shipping of homeless people, especially those who suffer mental…
Canada it is a "state"/provincial system. All provinces manage their own. Canada doesn't get inundated with Americans because if they do come, patients will be charged like private health care. If the patient's home province has universal health care, both province's will just work it out. In general, we don't dump problems on to other provinces. It's bad form and federal courts will fix that quick especially with so…
All of Canada has universal healthcare, which again makes Canada a completely different discussion from my earlier comment. There isn't the kind of huge discrepancy between provinces as we'd have if some US states had universal healthcare and some had the status quo.
To your argument about states suing one another - we literally already have localities giving mentally ill people bus tickets out of state, and that's been unable to be stopped via the court system. I'm not dealing in hypotheticals here, I'm talking about things that already happen.