It can't be denied there have been enormous improvements in aeronautics in the last 40 years, but compare them to improvements that occurred in the previous 40 years. Remember, this was a time when technological change supposedly moved slower than it does now. Except for avionics, aircraft performance has started to level off. Check out aircraft performance records and you will see many of them are still held by aircraft designed prior to 1980. The best dogfighter ever built was either the Crusader or the F-104 Starfighter, and the B58 Hustler still holds the transcontinental speed record, if I recall correctly. This is partly true because some of these improvements were no longer needed to fulfill a mission, or were not worth the extra effort or expense. But it is also partly due to the fact that we are reaching fundamental physical limits in materials, energy efficiency, and other physical laws. We are not making quantum leaps like monocoque construction, monoplanes, all-metal fuselages, jet propulsion, etc. any more.

Could we send an Apollo payload to the moon with a much smaller rocket today? Modern warships actually have lower top speeds than they did in WWII (again, partly because speed doesn't matter as much).
And the modern automobile isn't fundamentally different from the cars of the 30s (no turbine engines, infinite ratio transmissions, variable stroke pistons, etc). Granted, reliability and maintenance have improved, but repairs are very difficult and performance is comparable. Even economy hasn't improved dramatically: Carnot efficiency is still the same as it was in the era of steam.

I think our major advances have been in computer and digital control of technology, with enormous advances in biological sciences such as dna and genetics. The 40 year period that ends today looks a lot more like 1967 than 1967 looked like 1927. I really do believe we are pushing up against fundamental physical limits. I don't think science is going to stop, I just think the breakthroughs will start coming in other areas, perhaps areas we can't even anticipate. Who saw computers coming in the 40s?