I don't know where you got the information that Elon Musk was behind Shiba, but I think it's just rumors.
Yes, it may be just rumors, I do not know explicitly if he had anything to do with Shiba, but the talk on social media was that Elon Musk bought large quantities of Shiba because he tweeted a picture of his puppy (the Shiba breed) on Twitter, but Elon Musk denied that he owned Sheba.