The fact that they have built those businesses doesn't mean that they can draw informed conclusions on whatever they want. I doubt that Bezos has his think-tank of domain experts giving him background on every question he gets asked during interviews. Sure, if Bezos shifted his attention to healthcare, a month after the announcement I would give his opinions weight, because he's proven adept at analyzing situations quickly, given motivation. What's the motivation to learn about X problem in the world at any given time?