I think many, at least the folks in the article, have a need to be recognized and they aren't getting it elsewhere in their lives, so they continue working, able to make a contribution and get recognition from clients, colleagues, or others...minimally a paycheck that puts some value on their contributions. Me, I have no need to be recognized. My self worth is a function of how I value what I do day to day, not what others believe.
There was a time when I did need to go get out of the house, make the commute in to the office, and spend the day working. There I'd get to socialize and get my recognition. I did have a need for the recognition, getting a higher salary and bigger bonus, because that was feedback and showed how much my contributions were valued. Today, I no longer have those needs. I'm perfectly fine at home, alone or with DW, doing my own thing or something together. I get value out of using my time how I feel it will produce the greatest value for me, and it doesn't need to be monetary any longer. I have a small circle of friends I get together with periodically and am able to visit with family any time I like. All of my personal needs are being met without the job.