> One might ask why that is

Indeed.

It is one consequence of a highly atomized culture. I suspect it happens because individuals are expected to take responsibility for their care (basically, this is the human side of cost-shifting and corporate planning around the care gradient available to someone at a given wealth level).

To someone at the end of their life, money is usually less interesting to them than a few more days of breathing. So the market provides.

The explanation I've heard is that it's rooted in the cultural sanctity of life and how that translates to trying to preserve life at any costs (even when quality of life is no longer present).

To be clear, I'm talking about the absolute twilight of one's life that's reached regardless of levels of preventative care. I think there's potentially an opposite point that could be made: taking care of one's self can prolong this period and make it cost more. Someone who drops dead of a heart attack one afternoon won't have the same end-of-life costs as someone who gradually becomes enfeebled with age.