To be or not to be ain't always a question

Having almost always lived in countries with impeccable healthcare, I have a hard time understanding American resistance to the universal success of well-managed universal systems and have a hard time caring about the pettiness of congressional pageantry. But there is a question hidden in the debate that does interest me.
At the risk of sounding older and curmudgeonlier than I already am, I remember that people still died of old age when I was a kid. My great-great-grandmother, Hilda, died at 106 or so (there's a picture of five generations in one shot - can't happen too often). I was young at the time, but I don't remember anyone mentioning a 'cause of death'. It seemed quite natural that a >100 year-old body was just done. Even when Hilda's daughter, Gladys, died at around 88, nobody felt compelled to demand an autopsy. She was old.
Then I read today that "According to virtually any commonly cited value of a year of life, the increased spending (on healthcare costs/year of life since the 1970s) has, on average, been worth it." The same article also said "...it costs far more to prolong the lives of the elderly ($145 000 per year gained) than the young ($31 600), and the rate of spending on the oldest Americans has grown the fastest". * This is mindbogglingly bad economics. This tells us that the marginal value of years of life decreases after a point with age (i.e. as you become older and more decrepit, you value each extra year less - at some point you're begging for the end, as some of us might have witnessed before), but the marginal cost increases (paying for each extra year becomes more expensive as time goes on). When did we acquire this principle that life should be extended at all costs, and where does it come from?
I have a few theories, none of them well-researched, but they're hopefully at least plausible.
Theory #1: Despite arguments to the contrary, I reckon the world is a much more secular place than it was a century, even a generation, ago. Religions tend to offer some hope for continued personality (can't really call it existence or consciousness) in some form after death. This might be a consolation prize people would generally be willing to accept in lieu of heroics for the preservation of life, but those without faith don't even have access to it. As a substitute for eternity, people are willing to fight for every last second of a limited period.
Theory #2: Olson's old fashioned collective action problem: in a world of diffuse costs and concentrated benefits, concentration wins. Every doctor gets a lot of benefit (her entire salary) from a healthcare system, whether public or private, and there are far fewer doctors than people paying for them. As a result, the doctors are willing to fight harder for their interests than patients will for their own, which means that the flow of resources is skewed in the doctors' favour. Doctors get a lot of resources for treating the elderly, so they make a strong case for doing so.
Theory #3: Diffuse reciprocity: since each generation depends on the subsequent one for care when we get old, whether in terms of pensions or medical care, we want to set the example for how our offspring are to take care of us, and hedge our bets by overproviding care for our predecessors. On the notion that it's better to have too much than too little, we end up doing the current elderly injustice so that no expense will be spared when it's our turn (though we have little comprehension of how miserable we might be when we get there).
Theory #4: Senseless overconsumption: there seems to be a common idea that we could conceivably want anything anybody else could sell. Echoing Mallory's sentiment about why anybody would want to climb Everest, about the best explanation I can find for anybody wanting to buy a number of consumer goods, like anything with a celebrity signature on it or useless stuff like Tamagotchis, tis "because it's for sale". I had considered the idea that it might be some sense of entitlement, but I don't think it's that deep. Do old people and their relatives even frequently question whether treatment is a good idea at all, let alone whether any particular treatment is?
I could probably come up with more, but I think the point's been made. You wanna really save money on healthcare? Have the wisdom to know when it's your time (hint: if you're over 80, you're due) and the gravitas to bow out without herculean measures and croesian costs.

*If we really believed this, wouldn't we compensate all of the sacrificed innocents in war on the same scale? If an extra year of an old woman's life in the US is worth $145 000, why do the families of killed civilians in Afghanistan get as little as $210?