Yes, but the swing-out DA/SA revolver and the Browning-inspired locked breech semi-automatic pistol are much much closer than the other examples you cite. That fraction of "basic engineering" that's still included is much much higher in firearms. And the more minor evolutionary advances in firearms are also more likely to appeal or set themselves apart in the minds of firearms enthusiasts like us, and not the general population.
The problem with trying to compare cars, planes, and rockets is that the additional features grant completely new or expanded capabilities that are very significant against the basic function of the device. Airbags protect you in a crash, fuel injection extends mileage. The jet gets you there faster than the propeller. The space shuttle is "reusable" and lands like an aircraft over the single-use Saturn V (I know, don't get me started on the economics of it, purely an engineering example with that last one...)
For the record, while I like antiques too, my biggest desires are for modern firearms like Glock, HK, AR's etc., but no matter how much polymer, high end corrosion resistance, ergonomic upgrades like ambidextrous controls, lasers, lights, or tritium night-sights you put on it. The most modern .45 ACP you can think of ultimately does exactly the same thing as a 96 year-old 1911.
Throw a .45 caliber slug downrange between 850 and 1100 fps at the target. Polyganal rifling may add a few FPS, better steel may allow higher pressure rounds, the sights better aim, but none of the others will make that bullet fly better or father.
Although what you say about the advances in the technology behind the engineering do make me wonder if things like polymer over metal frames, and CNC machining, MIM parts etc. (and even simpler things like expired patents) has enabled to firearms industry to increase their profits and maintain it's relative health overall, against historically smaller sales.
