Talked not long ago, with a fellow involved in producing a major part for our upcoming hypersonic. He admitted that we have "some catching up todo".. Not much, but some..
Essentially, it gets the speed because the projo is sent into space, then returns like a meteorite.
From a web source..The Russians and the CCP cannot "rest on their laurels" however, with that lead, since they each have perhaps 1 or 2 operational examples, while we have a whole "family" of same, just waiting to be introduced.