People use to believe in previous Elon and not this meme promoter kind of Musk, he has deposit all his brilliant ideas on promoting shitcoins rather than focusing more own his on invention, he his confident because he feels there no more genius on the planet earth that's the reason why he is so confident, perhaps before anyone can match up with him may take some time, but that's not a reason to mess with people's feelings.
He is the world's second richest person and obviously he has a lot of followers. McAfee had a fraction of the followers Musk had and we all saw how he made hundreds of millions of $$$ by manipulating the cryptocurrency market.