In fantasy the abilities of wizards and sword fighters are plausible within the constraints & difference with the real world. Eg magic isn't real and people don

In fantasy the abilities of wizards and sword fighters are plausible within the constraints & difference with the real world. Eg magic isn't real and people don't fight with swords, so we're in an unknown territory where a large range of techniques are plausibly effective. You don't know a wizard so you can't really tell me this spell wouldn't work in this conflict, you know? But people do fight with guns, and the abilities and techniques of guns and what advantages they offer are well understood, pressure tested in real conflict, and easy to find out about. The area of unknown is small, and so mostly the plausible techniques are the real ones. You can tweak the plausibility by fuzzing off from real world uses with things like laser guns or muzzle-loading black powder, though that's still much better understood than wizard magic. You see a similar thing with fantasy melee too. Fencing is well understood even in the modern world, but how many fantasy sword fighters are recognizably fencers?