No one knows who is behind all this, just like Satoshi Nakamoto who we only know by name but we never know who it is.
However, if we talk about all cryptocurrencies with very large volumes of course this is not one or two people behind all of this, it could be that really rich people are investing behind the scenes, maybe we know one of them is Elon Musk but that's only one , what if there are dozens of other rich people who are here.