That's not true. Elon Musk is a physicist by education and even got into the Stanford PhD program (before dropping out to chase the dot com bubble) so he's not just a business guy. He's well known for studying any topic that interests him to the point of literal expertise and is notorious for micromanaging his talented engineering teams directly where he frequently contests their decisions based on scientific merit. And he usually wins those arguments because those engineers, who are experts in their field, concede he's correct. It's not the Dunning-Kruger effect, dude genuinely knows his shit. Of course he can't be an expert on everything (and his dismissal of nano science is clearly evidence of that) and he obviously didn't do the real nitty gritty himself, but to disregard how his own scientific and engineering ability has been a big part of what his companies have achieved (for better or worse) is disingenuous.
The reason the talented scientists and engineers beneath him are able to achieve the seemingly impossible goals he sets them is because he himself has the scientific background to know that the goals he sets are actually possible to achieve and he can prove it.
Not trying to be a fanboy or defending Elon's actions in the OP or terrible lack of PR filter, but credit where credit's due.