ITT: People thinking they have better decision making skills than the richest man on Earth.
It doesn't take being wealthy to understand what stupid business decisions are. That aside everyone who is honest knows that other people's decisions are responsible for his wealth. Every idea he has had for Twitter has reduced it's revenue.
You could have made the argument that Musk's success is due to other people if he had only had one such success. But the fact is that he struck gold with both Tesla and SpaceX and both happen to be in industries with incredibly high barriers to entry (automobile and Space respectively). He really is good at what he does, if awkward.