It's not even the US in general, it's SpaceX specifically. Only the US and China have demonstrated reusable rockets, and only SpaceX demonstrated the actual reuse, the cadence and the economy of scale that it brings.

It means the laws of physics allow it, and anyone willing to invest the time and fiat to accomplish it can. This means the world will no longer need to rely on SpaceX for inexpensive lift to orbit through reusable first stages, which is objectively good. No different then China working towards obviating the need for ASML for EUV semiconductor manufacturing.