If other people didn't have children who grew up to be doctors, nurses, etc, there would be nobody to pay.

Looking at those in my extended family that have reached retirement, this does not appear to be a given.

End of life care* is highly variable in duration and costs and many people do not adequately prepare for expensive endings.

* this is true of more than just care post retirement

Plus most of what needs to be done is highly informal and unstructured. Money can only buy so much. It can't buy someone who is going to actually represent your interests, rather than charging gobs of money for the illusion.