Eh its really hard to have the same argument over and over again when people do not even try to look at things from another perspective but I'll give it one more shot.
Canada does not spend as much money as we do on others things like defense nor has it been in as many military conflicts or a similar scale. Canada happens to be also a much smaller country in terms of population (40 Million) therefore it is much easier to implement a single payer model. The issue linked above is an example of a continuous problem that continues to happen in countries that treat healthcare as a right. Its not some infinite resource which is why shortages occur like they would with any other product that was in demand and given out freely. This therefore leads to the first problem which is inefficiency. Quality therefore dips and drugs either get more expensive or are switched to generics. This happened in Europe, France in particular. Should single payer be implemented, it should start on a state level so other states can see if the system is right for them.
Second big issue with single payer system is that it is unconstitutional. Politicians in both parties violate it all the time, I am sure liberals will be claim violation of the constitution now with Trump as was the tea party during the Obama era. Unfortunately it seems to be happening only when the preferred party is no longer in power. So if you want to put that argument to rest then amend the constitution and make healthcare part of it.
Third issue is that it is unethical to have a single payer system. It violates the natural rights which are right to life, liberty and pursuit of happiness. This is the reason why I am against most government regulation which restricts a person from achieving happiness or success. Surely you should ask if we are violating someone's individual freedom by forcing them into a healthcare system they do not want to be a part of. I know I wouldn't want that just like I would not want any of you to be admitted into a certain religion against free will. I also certainly would not want any of you drafted and sent to a foreign nation halfway around the world fighting for economic interests of select few or "national security".
Obviously I would like to try a free market approach which would significantly decrease insurance rates and cost of health care. I am sure most of you agree with me in that regard. Would everyone be covered? Yes, if they are willing to pay more just like with any other limited good or service. In many cases they would receive help from charities, religious organizations and medical corporations as they do now but in a greater scope due to lessening of regulatory burden. Would people still die? Yes, just like they do under single payer model as indicated above. Clearly no system is perfect but at least in the free market you can decide to opt out should you have that desire.