Those nations don't guarantee healthcare, they promise healthcare. More often than not, those promises are broken.
If government health care is so excellent, why do British and Canadian people (at least those who can afford it) fly to the United States to have surgery and cancer treatment? Why are so many people dying in British hospitals from simple post-operative infections, that could be easily prevented and easily cured?
"Free" health care will mean one of two things, possibly both:
(1) Sub-standard health care; or
(2) An enormous tax increase.