I don't mean this to stereotype but has there ever been an American billionaire who wasn't at least a tad bit nutty? And I don't just mean "views everything through the business prism," I mean absolute flakes to a point.
Look at how many billionaire sports team owners insert themselves into the process thinking "well, I'm a billionaire, so I understand sports", and they (more often than not) wreck the team. But you'll see this in every walk of life, too. Ross Perot, for example, notoriously made up stories that turned him into a standup, brave guy (his employees would call his tendency to tall tales "Rossing," where he'd make up a preposterous story about something he did, which his confidantes knew was going to blow him up once the news media figured him out). Vince McMahon clearly has pathological issues as to Ted Turner, Trump (and I'm giving him the benefit of the doubt since he alone is the source of his claim to be a billionaire; most billionaires on the record consider him "a clown living on credit"), Bill Gates, Mark Cuban, Dan Snyder, etc.
They're all just a bit nuts.