I haven't met a billionaire, but I definitely have meet people that fit this description. I don't necessarily believe that's the case for Elon, but it wouldn't surprise me. Story below:

As we flew to Mexico these three wealthy executives discussed multimillion dollar business deals like other people discuss last night's ball game or recent movies they've seen. To tell you the truth, I was intimidated—especially when the billionaire turned to me and asked, "So tell me, Ballard, what exactly is it that you do?"

"After listening to the three of you talk," I said, "I guess I don't do very much at all."

They chuckled at my comment. But none of them seemed to disagree with my assessment of the situation.

As our conversation continued, however, it became clear that, although these were men of good will who had done many good things in the world with their wealth, the most important thing in life to the billionaire was to accumulate more and more money, which appeared to be the source of his power and prestige. Wealth seemed to be what made him happy and proud. As far as I could tell, it was his passion, his obsession, his very reason for being."