Earlier quoted context omitted.
Joking aside, if I’m seeing more than one of these hypothetical professions, someone needs to coordinate my care. For myself, I trust me to keep everyone informed. Anyone else wouldn’t have the same incentive to do a good job. After all, I’m the one that suffers the consequences if there’s a mistake. :)
Age and cognitive issues may hinder you from effectively doing "a good job" of that.
Beyond old age, the vast majority of people are bad at taking care of themselves. So many people that it is not a moral issue. It is a systemic issue.
The problem is, you don’t need to take care of yourself, until you do. Society doesn’t prepare us for that. (I got to learn the hard way.)