I'm a big legacy person, so the entire family is interacting with each other. My current Legacy just tipped into the rich zone (with a net worth of 100,883 simoleans, to be exact). Right now, they're all asleep, but during the day, they're skilling or something along those lines.
When I played The Sims 2, I usually made random families and Motherloded them to infinity. None of them had jobs or anything, either. I can't remember exactly, but I thinkthey spent their days watching TV, playing games, and doing other non-productive things.
Outside of any kind of challenge and my cheat-y days, my rich families usually.. make more money, really. They were all either employed or self-employed (with the exception of the kids, teens, elders, stay at home moms, etc). My legacy families do the same, actually.