I don't really see any reason of Elon Musk to have hi own coin, cause he is already a big supporter of doegcoin, which has driven the price and popularity high and also with the hug buy he made on bitcoin recently. If Elon Musk should have his own coin, it will not survive for the long run in the crypto space, cause when the price shoots up very high, with pumping its price, the dump will be so hard that it will or could lead to the total death of the coin. As a big supporter of doge coin, he should keep it that way and make his profits and fame there.