Don't read this as a defense of Zuck or Musk, but some of the most brilliant people I've known sometimes had trouble getting thoughts out. It wasn't that they couldn't see their goal, but that how they thought of it was changing even as the words were leaving their mouths. Have you ever tried to explain while you were still working it out in your head? "See, it's kind of like A..., except that one part is closer to B, and that's interesting because, well, B and C have a relationship that's closer than A and C, so it might be more appropriate to say it's more C-like, except where A is..."

That didn't mean they were unintelligent. It meant that them trying to explain the flurry of ideas in their head was like me trying to type with mittens.

Of course, knuckleheads can also sound like that, but for different reasons. That kind of rambling doesn't imply that the speaker is a dumbass. It definitely doesn't guarantee that they're a genius.