He takes questions at Tesla earnings calls that other CEOs would delegate to lower level executives, and can talk about rocket science when prompted (see Tim Dodd's videos). That's not to say he's an expert on everything, one thing to note is he's also been working at those companies since the start. In my view, a big part of why his companies are successful is he actually does understand the product portfolio to a great depth that most CEOs who simply do management don't. I'm not talking to the level of "I can code this myself", I simply mean "I understand the software used to make this, how it talks with X and why we do Y instead of Z". It's easy to bash on people because you don't like them, but it doesn't make for a convincing argument with blanket statements like that.