There is ultimately a monetary value of extended life.

In single payer systems, that’s determined by a body whose responsibility is to provide the most effective healthcare to all its citizens given a limited budget.

In the US, the monetary value of extending your life is proportional to the amount of money you spend on your health insurance (and appropriate actuarial tables).

Both systems have flaws.

Both systems have flaws? True, but it’s a false equivalence. There’s a reason why there’s only one country in the world where insurance company CEO’s have to hire security to walk around in public.

Not really. At the end of the day, in both systems, the person paying for the healthcare decides what healthcare options are available to the patient. In the US, the patient themselves (or their insurer) is paying.

In other countries, it’s often the health service itself that is paying.

Don’t get me wrong, I believe the single payer system is infinitely better, but for a small number of people, it will lead to worse healthcare outcomes.

It's not "both" systems, it's at least four. Canada is private doctors, public insurance. In the UK, the public system includes the doctors as well. France is not single-payer but has a system somewhat similar to the ACA, with private but nonprofit insurance, an effective mandate, a national price list for health services, and a prohibition of claim denials for anything on the list.

A great book comparing eight national systems in The Healing of America by T.R. Reid. It references stats showing the French-style systems get the highest quality results, with reasonable cost. Japan and Germany have similar systems.

Exceptions don’t make the rule.