The SR-71 was designed and built in the 50s. Any sentient being knows that when it was finally replaced that there was something better out there.

Kinda reminds me of a conversation a coworker had with a submariner friend of his. They were driving down the freeway and my buddy asked how fast a sub could go. He was told "can't tell you, that's classified. But wed be keeping up".

There is a lot we don't know, probably a lot we shouldn't, but it emphasizes how important it is to keep informed and to elect people of quality to oversee.