Overall I like Elon Musk (although I've never met him), but people seem to think he's the über-engineer when really he's the über-salesman.
Seems like an engineering achievement to me.
If you read the biography, there have been times when an engineer has said "I can't meet these requirements," and he said "Ok, I'll do your job AND my job, and I'll get it done." And he did.
I think anyone believing he's not an extremely talented engineer has not read much about him.