I'll let the person(s) you are referring to speak for themselves.
Getting back on topic, how does one define work? Owners, particularly key men/women, work 24/7. If they were lawyers even time spent sleeping can be considered billable hours.
There is a truism that goes you only get
really rich when you sell your business. Going public falls under this. Sitting on a pile of cash is still the best measure. The bankers in the fancy suits are just their intermediaries. The really rich build and sell or buy, build up and sell. Those that retire to enjoy the fruits may not work so much, those that continue building do.
Reminds me of the Chris Rock joke about Shaq and Dr. Buss.