It is telling that the SR-71 has not been replaced with a better and faster plane.
It appears that without Kelly and his organization, the government/contractor world is simply incapable of the task. In spite of material sciences advances, computing and CAD advances, etc., not only can today's system not produce an improved version, it would not even be able to match the specs of the SR-71 in a new design today.
Of course some may say that the successor may exist but is so secret no one knows of it, but that is extremely unlikely. If it existed whoever created it wouldn't be able to resist taking credit.
The use case for the Blackbird has (mostly) gone away - iow, we don't have MAD and a burning need to spy using airplanes. The defense procurement industry ( aka the Military Industrial Complex ) is a major... victim of Baumol Cost Disease, and those two taken together...
no indictment of the practitioners there; it's just all but inarguable. If you work in a defense company, you'll either adapt to "do" contracts/procurement or you'll be gently pushed out...
Yes, it remains to be seen if the SR-72 will ever become a reality. As an engineer I believe it is possible to make such an aircraft a reality, but I have no knowledge of the program beyond what was stated in its announcement. As for the possibility of an already extant replacement, anyone who revealed information on such an aircraft without authorization would be risking their freedom (and possibly their life).
Or...hyper-velocity, fly-over, manned surveillance platforms have been replaced by increasingly sophisticated surveillance satellites, non-fly-over surveillance technology (e.g. SLAR) and unmanned drones, making an undoubtedly immensely expensive, manned SR-71 follow-on superfluous.
That or we got stupid since Kelly died. One of the two.
The original studies of Baumol Cost Disease were based on the idea that the production of symphonic performance has had no productivity increase since ... well, ever.
When asked why there are no "variety" shows on television, Glen Campbell ( of the "Glen Campbell Goodtime Hour" ) stated that they were verging on economically infeasible while his show was on, and you certainly couldn't do that today. My understanding is that "The Carol Burnett Show" had this problem and it only ran as long as it did because it was CBS' flagship program. "Carol Burnett" was not a classic variety show using ... a dozen artists per program so it was probably less expensive than Campbell's.
I'd expect the same has happened in aviation. Now, is that the same thing as "we got stupider"? I can't say.
No doubt, satellites can perform the role of the SR-71.
My point is that the system we have in the US could not create a new SR-71 class airplane right now, in my view. It would run over budget, miss the performance targets, and be cancelled.
Actually, satellites alone can't do what an SR-71 can. Satellites aren't an ad hoc intelligence solution, since they are periodic in their orbit and can't image something they aren't on-station to see. But combined with other tech, they replace the SR-71 nicely.
As to your "point", it's trivial to say "we can't do something" when we haven't tried.
It appears that without Kelly and his organization, the government/contractor world is simply incapable of the task. In spite of material sciences advances, computing and CAD advances, etc., not only can today's system not produce an improved version, it would not even be able to match the specs of the SR-71 in a new design today.
Of course some may say that the successor may exist but is so secret no one knows of it, but that is extremely unlikely. If it existed whoever created it wouldn't be able to resist taking credit.