I think he's successful because he's a rich guy pursuing cool ideas and actually going forward with the execution. All of the high level ideas I've heard from him are "obvious" stuff - electric cars, rockets, tunnel boring, hyperloop, that lots of us imagined when we were kids. The difference is that ideas mean almost nothing and it's actually following through with execution that's important. He seems to be good at actually doing stuff, not just talking about it. I certainly never thought of him as an "engineering genius", and even if he was, that would be mostly irrelevant to his ability to lead billions or trillions of dollars worth of companies.

It's certainly in Paul Graham's interest that people who cultivate cults of personality continue to be treated like royalty.

Sounds like a liability to Tesla and SpaceX. They are just one bus accident away from irrelevancy. I always assumed Musk was good at creating a company culture where people are innovative, which could in theory be kept alive even if Musk wasn't there anymore. Not so much when all engineering relies on his ideas.