Get a new, non-founding CEO has worked wonders for lots of companies. There are very few (possibly zero) people who are "the only person for the job".
Your point is valid though, and I do think someone could go in there and take over his job effectively. That doesn't mean there won't be a period of relative instability while that transition takes place.
Musk may be brilliant, but he's got a long history of a slippery relationship with the truth.