Like all powerful people in all of history, something is broken in their brains. They would be happy to rule over the ashes of civilization as long as they get to call the shots. No amount of actual failure will make them think any of it is their fault, because they're a genius, doncha know?
Like Jim Jones, they are true believers in their own bullshit, which is part of why other people find them so easy to believe, because there is never any doubt in their own minds that this is the right path. Jim Jones didn't just kill other people in his name, he also killed himself.
All these billionaires suffer from the same malady, believing their own bullshit.