Andrej Karpathy (ex-Tesla head of AI) talked about this recently. "I think Elon is a very efficient warrior in the fight against entropy in organizations". https://www.youtube.com/watch?v=mbxladysbTE

John Carmack, "Elon is definitely an engineer. He is deeply involved with technical decisions at spacex and Tesla. He doesn’t write code or do CAD today, but he is perfectly capable of doing so."