We cannot even say they do not have power, or amount of money because they actually do, but it is not just realistic for them to create a cryptocurrency for the whole world to use. Firstly, Rothschild totally tend towards centralization, and that means this would be highly controlled, and unless they are bound on shoving it up everyone and forcing them to be used all over the world, which we both know cannot happen, it would end up being as useless as XRP because no one who supports the idea of decentralization and is sensible enough will give it a face.
Why are you so sure it can't happen?
If I put on my triple layer tinfoil hat and I suddenly understand that indeed the Rothschilds control everything from banks to governments to Charlie Hebdo why would they not be able to impose this?
Central banks have imposed fiat money and 99.99% of the population has never thought of using something else, what would be the problem with changing that to a centralized crypto?