Assuming they are still fully capable, I'd say it's no one's business but their own if they want to keep working.
You are absolutely correct. A productive faculty member at 73 has no less place in an academic faculty than one at 43.
Chaosphere's suggestion that this scholar should "research on his own time" is laughable. So if you like what you do and are effective at it, the advice is to do it for free, drawing down on your retirement funds.
Apart from being transparently ageist, that kind of comment exposes a shortcoming with today's crop of aspiring academics. Academically strong, they have been lauded for their scholarly skills for many years. But they lack life experience outside of the academy. And so there is no internal muscle to filter ludicrous statements like "old people should work for free" or "animals rank in priority to people".
"I thought it, therefore it is gold" is not a research methodology.
I will try not to take offence from your statements.
I have worked in academia, in a hospital, selling cars, and driving a forklift on night shift at a warehouse. I am not sheltered when it comes to work ethic.
I did not mean on his own dime, I meant not taking up a slot in the faculty pool for teaching subjects / tenure positions. Senior faculty are valuable, but it is really hard for us young academics to get a job when none of them ever retire.
Oh and animals do rank among people. They deserve respect just as much as any other living being. My care for animal rights has absolutely nothing to do with a discussion of academic jobs. Please stick to the subject.
I am just terrified and dismayed that after putting in as much schooling as I have, and busting my ass for so long to get to where I am now, that it may be all for nothing because the faculties are just full of old professors who typically [there are many exceptions to this I know] are much less productive than younger / non tenured academics. Tenure is like the nobility - you strive to get there, you work hard to get there...and by chance if you do...then you can rest as you have made it.
Yes, if you are older and still producing and teaching full time, fantastic. Keep going. But in many cases, this is not so. My own faculty is guilty of this, as was my previous one.