Yes, aerospace development went in "different" directions, but in many instances those directions were cases of adopting new technologies to further enable existing platforms. Today, most military aircraft don't go much faster than about Mach 2.2 - mostly because up close air to air combat typically takes place at below supersonic speeds. So what we see is essentially gradual improvements in established platforms - often courtesy of improved computing and materials technologies - and not radical jumps in aircraft design. The military combat aircraft of today closely resembles what existed ten, twenty and even forty years ago.
Any quick survey of the aircraft history of the 1950's shows that decade to be a "golden age" of aircraft design. Rocketry and spacecraft are very similar to what was produced in the 1960's - with refinements in materials and associated technologies.
Other than being unpiloted, what is so revolutionary about the Global Hawk or Reaper? They are essentially variations of reconnaissance aircraft without pilots (and I'm not putting those technologies down - just saying that they are not revolutionary). As for reconnaissance satellites, that idea goes back to the late 1950's and early 1960's. Back then, film canisters were even dropped from space and caught in the air by aircraft. Now that's kind of revolutionary. Again, what we've seen then is incremental improvements in technologies that make these platforms ever more useful, but the essential platform remains the same.
For it's time, an aircraft like the XB-70 was quite revolutionary. It was conceived in the 1950's as a high-altitude waveriding bomber that could fly three times the speed of sound. It was built largely out of stainless steel, honeycomb sandwich panels, and titanium (a very difficult metal to work with- even now). It was designed to use a phenomenon called compression lift, which would be achieved when the shock wave generated by the airplane flying at supersonic speeds would support a portion of the airplane's weight. It represented a considerable jump from anything flying ten years earlier.
As for stealth, the mostly titanium SR-71 included refinements and materials to reduce detection by radar. "Stealth" research is almost as old as radar, and during the 1960's this Mach 3+ aircraft was designed in such a way so as to reduce its radar signature - decades before of the F-117, B-2 and F-22. Sure, these aircraft are more capable of avoiding such detection, but their capability is a product of evolution, not revolution.
A for the B-2 flying wing (which is subsonic), let's not forget such early examples like the Northrop YB-49 (1947), the Northrop YB-35 (1946), or the German Horten Ho 229 (1944) - the first jet-powered flying wing.
At the same time, what do we see in commercial passenger aircraft? What we have is incremental change. Most people would have a tough time distinguishing a an A-320 from a B-737, an A-350 from a B-787 from an A-330 from a B-767; but everyone would instantly see a big difference between any of those aircraft and Concorde. Yes, the technologies have improved considerably on contemporary aircraft, but the platform is essentially the same. The commercial airline business is a very conservative, so even today there is no strong impetus for much radical change (see the case of the Boeing Sonic Cruiser).
I recognize the improvements in allied technologies - and I certainly would not put them down - but Hipster's point is certainly not wrong or unfair.