They're still doing exceedingly well, so it must not have hurt them. I think it takes a small but stable company to pull it off. Maybe they have stopped doing it by now, I don't know.

These people cared about their work a lot, and they enjoyed doing it. Not sure which way the causation goes though...

Edit to add: the rotating managers I'm referring to were doing budgets and performance reviews, not creating business strategies.

I’m also intrigued. I’ve seen this happen several times but always de facto: someone would become a manager as an experiment, try it for a few years, and then (usually) decide to stop.