Why Do We Expect Them To Be Knowledgable

Even if we grant that the various techbros (Zuckerberg, Jack, Musk, whoever else) are geniuses at what they do instead of people who just won the lottery (certainly true of Jack, largely true of Elon and his paypal money), when did we start expecting successful businessmen of any kind to be modern Renaissance men? I know we generally have deference to rich guys in our culture - they must be brilliant! - but brilliant doesn't mean brilliant about literally everything. I don't even think we expect people who run publishing houses or cable news networks to be brilliant in the way there's this expectation that the techbros are brilliant, and there's more reason to think those types have a breadth of knowledge (whether they do or not). Zuck probably doesn't know anything about anything and I have no idea why we would expect otherwise?