> It says something about society that asks people to work well beyond their retirement age.

I dont think that's what's going on here. If you click on OP's profile you'll see that he's written a bunch of books. He also mentions Common Lisp and Racket, not exactly go to languages for soul-less corporations. My take is he's doing it for the love of the craft.

I aspire to do this too when I'm at that age. I've been through a few career iterations with the only constant being is that I love to make things.