Are they? I feel like this might be a little bit like the myth that psycopaths are smart. Incidentally, studies have found a higher concentration of psycopaths in roles such as CEO of big companies. I'll concede that billionaires are probably on average a little bit smarter than, well, average. But they're not a hundred thousand times as smart, despite being worth a hundred thousand times more.
Is it a coincidence that nearly half of all billionaires inherited a large part of their wealth (or all of it)? And while the rest didn't come from super-rich families, most of them certainly had a plethora of opportunities to succeed. Mark Zuckerberg is lauded as a self-made billionaire, but his parents were a psychiatrist and a dentist, he attended private schools and summer camps, and had a software developer as a private tutor (I'm sure that came in handy). He surely made the most of his opportunities, but even so he had opportunities that the vast majority of non-billionaires simply don't.
Make sure the wealthy pay their taxes by closing loop-holes and making it harder for money to make money simply by... well, being money. Regulate their business so they do not take advantage of their workers. I'm not looking for some kind of Red Scare vision of Communist sameness, but it is possible to make sure people from different backgrounds have the same opportunities, or failing that at least more similar opportunities.