Good write-up. It's generally why I don't study anything after WWII in terms of warfare. As insensitive as it is to say, I don't find it interesting. In most cases for me, large-scale battles tend to not make any sense when there are nuclear bombs, futuristic rail guns, you can get sniped by a "rod from God" literally sent from outer-space with centimeter-level precision, sniped from some crackshot from one of the ten thousand windows in the 30 surrounding skyscrapers, blown up by a random stray grenade or missile, hit by a random stray bullet—the list goes on.
I'm not sure if depersonalization (I thought you were going to start talking about the awful anxiety symptom I have sometimes experienced lol) is the word to use; maybe impersonalization? Every combat encounter in hand-to-hand fighting is a personal, calculating ordeal between two human beings who are staring into the eyes of the other person. Of course, that's a bit dramatic, they're probably looking at other important things, studying the armor and weapon of their opponent, their stance, looking for an opening to strike or preparing for an incoming blow, etc. Still, shooting a person whom you cannot even *see* from 100 feet away, or blasting them off the face of the planet with a drone strike from the opposite side of said planet, is entirely different than besting an opponent in physical combat and feeling your sword cut through their neck, their flesh, their bone.
Anyway. It was nice to see that I'm not the only one who has thought at length about these matters. A lot of modern action fails to entertain me because it feels so improbable. (With Star Wars I can understand it, because of the nature of Clones and Droids, so there are certainly exceptions.) I think sci-fi has its means of getting around these hurdles of a gunpowder+ battlefield (i.e. Halo) with the use of defensive capabilities that can compete with the weaponry, such as energy shields, Mjolnir "super" armor, etc. But generally it seems like action that is set today tends to be small-scale, like a Navy Seal team or some other special operations force, which often puts the character-soldiers in situations in which gunpowder loses most if not all its supposed advantages.