Mrs MP tells me this is true in all "professions." I think it's to do with power but Mrs MP believes it is just a matter of making sure everyone knows "how busy and overworked" they are.
Mrs MP is a nicer, less cynical person than me. Of course, that does not mean that she is necessarily right. Sometimes the cynical are cynical because they are right.
Letting people know ‘how busy and overworked’ they are is something to do with power.
I have often considered charging my doctor my hourly rate when I am made to wait past my appointment time.