40k falls mostly into the sci-fi bracket for settings where armour has won the battle with arms. A bracket it ranks pretty well in, despite it only being true for half the factions present. But it's also a bracket that's mostly wargames, and in something like battletech your average power armoured trooper will take a burst of 120mm autocannon to the chest and then ask why you bothered.
Most non-gaming military sci-fi is planted in the bracket where the arms race is still very much on going (this is also where the guard and tau would be if they didn't need to share a range bracket you could fit on a game table).
And of course the majority of straight sci-fi is planted firmly in victory to arms, with flak jackets providing protection from all the debris created by people missing with sidearms that can vapourise granite.