Some white-collar professionals enjoy continuing their work past retirement age. It can be stimulating, high-leverage, and I have often seen them contributing at key moments without spending much time at the office. The accumulated wisdom and political capital of many decades at the wheel makes a difference. I've also seen blue-collar workers keep at it past retirement age because of their finances or some other compulsion despite arthritis, weakness, bad sight etc and rue every moment. Let's make sure we understand that not every craft is heaven and not every corporation is a hellscape.

I worked for others in a corporate environment and it was often a joy, but the problem is you don't always get that lucky and even if you do, the environment can change around you from year to year and a perfect job can turn into hell. And corporate engineering jobs have become so filled with stupid bullshit that the career I had and thrived in may not even be possible anymore.

I'm not set up to work for myself, my ideal is for others to worry about the business, and give me projects I can work on with freedom.

If you're making money from that craft it means you have customers. And bad customers are their own kind of hell.

But in most crafts they are easier to avoid or mitigate.

I too had a boss in his 80s who was the patriarch of the company, he had one son who was a partner when I was there. By staying involved, he could live like gentry alongside his clients, going on interesting trips, and participating in interesting ventures, and being invited to many parties to mingle with the local high status. I don't think pouring his own nest egg into similar ventures would be the same. It was the difference between upper class rich and middle class rich.

His son developed his own upper-class tastes but had no interest in mingling business and pleasure. He had an interest in making international big game hunting trips frequently. Whereas the father's extracurriculars always involved the business, generating leads, etc.; his adult son's extracurriculars were just burning money as a demonstration of status.

Those are the two reasons why he would not step away.

That job was insightful but also depressing because I could recognize my own inadequacy. I want to go home after an 8 hour workday. Not a calendar of dinner with one city council member a week, a second dinner per week with a bank president or similar ilk, going to lunch with various other people, outings, parties, hearings, conferences, etc. It's both exhausting and anxiety-inducing cause of FOMO. I'm sure that's a third reason of why he would not step down.

More likely they retired because they found out they had little time left.