Hypersonic Missiles Are Game-Changers, and America Doesn’t Have Them
wsj.com
wsj.com
It stands to reason that a country would not reveal or even go as far as to deny the existence of weaponry that would be cutting edge or even alter the existential beliefs of the human race.
Since then (largely due to the efforts of the military industrial) weapons are developed and put on a shelf to be used "when the time is right". There are many others that are being used that you have no indication of their existence.