We love what we do.
Some folks have a grand plan for post retirement that involves fleeing "the man" (awesome for them, if they so dislike their employ). For others, though, "retirement" or "money" isn't the end goal.
I work in finance so I won't self exemplify. We know medical personnel who make serious coin, have great financial health, and would "check out" if they stopped working. They love it. A friend is a first chair in a major world symphony. She never wants to stop. We have several engineers in the family who tried to retire ... and then ended up forming consulting firms and run them late in life. Another member of my family is a writer some of you probably know well - he'll die with a pen in his hand. And another is a dean at a college some of you have attended - he loves his work.
Yes, these are anecdotal. But, if just in my family, I can think of 8+ folks who realize that retirement isn't an end to itself, there are others (especially at the early age of 67, which I don't consider old): many others.