I'd say Jack Dorsey is good reference. People with his kind of knowledge. Elon would simply supervise less and less as time goes by. He wouldn't be the only person owning a media company run by a CEO. He's sort of like Bezos now actually, with Amazon (= Tesla), Origin (= Space X) and WaPo (=Twitter).
Apple is doing better than ever now, even without Jobs. Tim Cook came out of no where as far as I'm concerned (certainly not, but I wasn't following).
I just go by how he casually says he should find someone by the end of the year, stays positive about it, and keeps working 80-hour weeks or so apparently.