Eons ago I was listening to either Long John Nebel or Barry Farber. There was the usual discussion about all things UFO.At the end of the night one guest asked another, a Brit sci fi author, what nation or agency would likely be investigating this type of tech. He answered immediately “ the United States Navy”. The Navy he opined had a long history in investigating and developing advanced tech even if they had not publicized their results. So if there are to be hypersonic weapons I would not be surprised if the Navy not only had them, but had a means of defending against them.
The Army has had an hypersonic weapons for a number of years. The weapon itself was tested and proven to be effective. The weapons carrier, the fire control systems, and other essential elements of the fielded weapons system may or may not have been developed, tested, etc.
I don’t know if the delay was money, technical integration, or bureaucratic infighting. It may be all of the above.
I’m pretty sure that the Navy was looking at the same weapon.