I think the unspoken implication is that being a billionaire means having an inordinate amount of power, such that immoral behavior like this becomes almost a given, because you can literally buy your way out of consequences (if only up to a point). Maybe the pertinent question is less, "How do we stop there being billionaires who succumb to the temptations of their unfathomable amounts of power?" and more, "How do we stop there being billionaires?".