I don't think it's comparable, But its no doubt that Elon Musk is a super-rich individual, and all his fortune comes from the stocks of his companies real-world mainstream companies like Tesla, SpaceX, Neuralink, The Boring company, etc. 

I know that It's a sarcastic example if Elon will put his fortune into Ethereum which is, in reality, it's very impossible to happen, Anyway, I have doubts about Ethereum MarketCap being exactly like that? don't get me wrong but it's not realistic because crypto prices are fluctuating faster than any other assets that's why I never look at that marketcap comparison.