I like when people are able to finish my suspicions in a more complete way than I think I could have come up with. The super rich are so rich it's not even fun anymore. The next challenge for them is total control like you mentioned.

The conclusion that I came to was that the real reason they wanted so much money was to fund big changes and most are now showing their plans. Jeff Bezos and Elon Musk want the new frontier of space exploration, Bill Gates, etc want to own this world.