I was also going to add, could it be that the USAF, CIA, Gov, etc
had two programs in succession? one in the 1970s/1980s and one in
the 1990s/2000s?

just as the U2 covered the 1950s/1960s and the SR-71 covered the
1960s/1970s.

it's not unreasonable to think there were overlapping and/or
successive programs.