People follow him because he is the biggest man in cryptocurrency What he says happens. Is one of the people and when he speaks it is clear and easy.
He is a successful man in cryptocurrency The coin he talks about gets his price up. a few days ago he tweeted about dogecoin and check his price where are you. I think that's why people follow Elon Musk.
he is in the lists of the richest man on earth, and now he start talking about cryptocurrency on twitter
thats why a lot of people following him mate, of course if he mentioned an altcoins in his twit for sure the coin will spike up
also, his company just bought bitcoin in huge amount too