1) My wife has a chronic health problem. What guarantee do I have that if she needed treatment, for that or something else, that insurance wouldn't find a way to weasel out of covering it? Also, eventually I would lose coverage under OHIP, the Ontario Health Insurance Plan, after an extended absence (1-2 years? not sure exactly), so going back to Canada for treatment would not be an option forever.
2) My health insurance would be covered and sponsored by my employer. I'm already dependent on my employer for my income. In my mind, also depending on them for health care coverage is putting too many eggs in one basket.