He's only the "richest" man in the world because of the inflated valuations of his companies. At some point the market looks like a dog chasing its own tail:

Q: Why is this stock so valuable? A: Duh, because Musk is worth a kajillion dollars and everything he touches is gold!

Q: Why is Musk worth a kajillion dollars? A: Because he holds so many shares of extremely valuable companies, silly!

There is this, but he is also a quasi-government figure. As Trump weakens he will reappear in that sphere.