No one wants to wait when it's their problem. Take kidney stones, for instance. I've had those damn things and while not life threatening the sumbitches HURT.
Down here, I see immense amounts of waste. The local hospital chains rent billboards, take out two page newspaper ads, have huge TV ad campaigns (there is one which shows an EXTREMELY busty blonde sliding into an MRI. Freud, anyone? ), use internet advertising (every time I log on Bon Secours St Francis has some video at the right side of my screen) and advertise stuff like valet parking to attract customers. a couple of the hospitals down here look like something from a resort; high end tile, marble everywhere, huge fancy chairs, gigantic salt water aquariums, the list goes on. That stuff does NOT add to the quality of care one iota (yeah, yeah I know, nice surroundings blah blah blah) but you better believe it costs a wad. I figure at least 20% of medical costs go for incidentals like that. I'd gladly forego ficus trees in the lobby for a 20% reduction in health care costs.
As mentioned, my dad recently died of cancer. I won't bore you again with the details but I will say that the last three months of his life were very expensive. We are still waiting on some chemotherapy bills to come in for a final analysis of the costs, but $43,000.00 is for sure right now. We may be ale to negotiate that lower. As mentioned earlier by a couple of other posters, the very end of life is where we rack up the highest bills. Unless I miss something entirely, I have never heard of a private insurer backing out of those costs. Why? It's because they are contracturally obligated to do so, would any of you buy an insurance policy which says 'after age so and so you are on your own, buster, even if you are still paying premiums'?
So what happens when the patient's wishes are taken out of the equation? Now we get to the allocation of resources. The amount of money is finite in any system: private, public, a mix, whatever. An 80 year old in poor health would be occupying a hospital bed better used for a 30 year old who needs to convalesce after a car wreck. So just how long do you think it would take for rules to be put in place saying 'based on this formula which says you are no longer a productive member of society and it doesn't matter even if you are the one who's paying you aren't worth the cost to the rest of society, here's some pills, now go home and die'. That's what you'd eventually get with a single payer tax supported system. BTW, there are already formulas in place for determining the 'worth' of a human life, generally used in wrongful death lawsuits. Not much of a stretch to apply those in the other direction.
Regardless of whether that's right, wrong or necessary (and I think it will be eventually ), people will not stand for that. The saying goes 'you can judge a society by how it treats its elderly'. Used to be, the sick, lame and elderly were kicked out of the tribe to fend for themselves which is pretty much the same thing the lower animals do, if there is a reason for the herd to move on if one of them can't keep up they are left behind and they die. That's supposed to be one of the things which separates us from the lower animals.