You think that that billionaires have earned their wealth through extraordinary achievements. Since you imply that billionaires must be smart, productive and hard-working, they seem to be highly qualified for politics, too. Such a “guardianship” or elitist perspective has a long pedigree – Plato espoused it in The Republic; more recently, Jason Brennan defends it in Against Democracy.
Robert Dahl, in Democracy and its Critics, developed one of the classic arguments against “guardianship”: “Much of the persuasiveness of the idea stems from its negative view of the moral and intellectual competence of ordinary people. But (…) it does not follow that potential guardians of definitely superior knowledge and virtue exist, or could be created, and could be trusted to rule on behalf of the the public good.” (Dahl 1991: 65)