> It seems so strange to me to hear stories about people suddenly coming into a bunch of money and not finding contentment or even ending up depressed. If I could afford to retire today, I would do it in a heartbeat and I'm pretty sure I wouldn't run out of things I want to do.

Different goals. If your goal is pursuing hobbies or a certain lifestyle, work is a means to achieve that. Getting money just lets you skip the work part.

Their goal is creating a successful business. Having money and leaving the business means now they have no goal.