A lot of the comments in this thread are saying it's because the rich are passionate about what's making them money, or their work is like a hobby to them. I t

A lot of the comments in this thread are saying it's because the rich are passionate about what's making them money, or their work is like a hobby to them. I think "work" as it is said in this article, is maybe better read as "making money". The article is more about why do the comfortably rich continue putting in so much effort to make even more money. Sure, they can continue to do hobbies or whatever and call it "work", but why continue trying to make a profit, instead of paying employees more, or running non-profits, or pursuing hobbies in ways that doesn't generate them more massive amounts of money?