The rub is that we're all terminal. So exactly when do you start withholding life-saving or life-sustaining care?
My father had a stroke. My mother had a lot of difficult medical decisions to make when it happened and we (their six children) helped talk her through my father's wishes, the long-term prognosis, etc. In the end, my father lived just long enough for all his children to get into town (a few days). If my mother had made different decisions, he'd have "lived" many months more hooked to machines and oblivious to it all.
But who should get to make that decision for you?
Very similar experience I had with my parents. I had medical power of attorney for both, as well as a Do Not Resuscitate order. Neither wanted to live confined to a hospital bed or past the point where they couldn't lead a normal life, and made that clear in both documents.
Dad suffered a series of strokes over a three year period and the paralysis eventually got to the point that he started choking on his food. His wishes were respected and rather than have an IV or feeding tube installed, he was allowed to starve to death. Heck of a reward for living to just shy of 80.
Mom was recovering well from a stroke when she had another surgery, shortly after which she went into cardiac arrest. The doctors applied heart paddles and proceeded to shock her back to life, but still no pulse after four minutes. Her partner (not married) tried to get them to stop and let her go, but he was forcefully taken from the room (I was not there). After five minutes her heart started again, but when I next saw her it was clear she had suffered severe brain damage. The doctors violated the DNR even in the presence of someone advocating for her wishes that no extraordinary means be used to preserve her life.
So with respect to that aspect of who decides, YOU do, but only if you go to the trouble of making your wishes known to your children and care givers. Just down the hall from my mother's room was an old gentleman who had evidently not made such declarations, and his family was bitterly divided about letting him pass. Eventually it was decided to let him go, but he somehow revived and went home a few days later. But not before his family had done much hand wringing over his fate, all of which could have been avoided by a clear medical power of attorney.
As far as who pays, insurance is supposed to spread the cost of claims over all the members of the insurance pool so that no one person suffers financially. But when insurance companies are able to refuse insurance to those with pre-existing conditions or charge outlandish premiums to those with unfavorable genetic make up or family histories, a growing number of people are left uncovered. As are people that refuse to purchase health insurance, regardless of their ability to pay either the premiums or medical bills. The ACA was supposed to sort all this out, but the central tenant of making the pool as wide as possible to impose the minimum financial burden on everyone has been distorted by political wrangling, we're still a nation where significant numbers of people do not have health insurance.
And as to cost/benefit, some doctors are very frank when asked if the treatment has significant chances of improving the patient's quality of life. Others hide behind their Hippocratic oath and play super hero, causing great pain and suffering as a result. In my parent's case, the super heroes involved succeeded in causing long, lingering, painful deaths that lasted about three years from the onset of the first stroke. All that could have been avoided with sane Death With Dignity options as directed by a Medical Power of Attorney and enforced by a caring family member or advocate.