Now theoretically I know they are different, or should be different, but is there really much of a difference between a corporation seeking only profit and a government? Well, aside from one having more power than the other.
There is a HUGE difference. A government run plan, because not concerned with profit, is far less likely to deny care. In fact, in Canada is unheard of for somebody to simply be denied care. There are cases of people not able to see doctors for whatever reason, and other such things, but nothing that comes directly from the government run plan. In fact, OHIP will pay for your treatment at an American hospital if you must go there for some specific treatment or operation.
When a corporation is in charge is where you get into trouble. An insurance company automatically wants to do everything it can to not cover you, or at the very least cover you as cheaply as possible. This is where idiotic things like pre-existing conditions comes into play. Pre-existing conditions is like a foreign term in Canada. Another by product, is that hospitals will often not treat you, unless it is truly something immediately life threatening, because they fear not being able to be reimbursed unless you have proper medical coverage. And if they do treat you without you having proper coverage then you are stuck with a bill of thousands and thousands of dollars, which will often bankrupt you. I have never heard of an Ontarian having to go bankrupt to get medical treatment in this province. In the US it happens on a daily basis.