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.
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.