I can understand not wanting dishes lying around all the time and also not wanting staff around all the time.
I sort of see his job (what he chooses to make it anyway) as helping other people do good works by expanding their resources. I'm not sure that benefits from a 110% time commitment.
I'm a CEO who does his family's dishes as night. It keeps you grounded. It's a good message for your kids that in spite of their wealth they should clean up after themselves. It makes a connection to the millions of hard working people out there. Finally, if your wife cooks dinner (as mine does), it shows appreciation for her work and effort. I use a dishwasher (as does BillG most likely) but there is still plenty of work like pots & pans.