Not understanding military strategy or how it would be fundamentally altered by fire-breathing dragons/magic unicorns/vast interstellar distances/bombs that can annihilate planets

I could not get over this in one of the new Star Wars movies when they establish that you can use hyperdrives on a ship to easily kamikaze a star destroyer. Like, writers, you just invalidated the entire Wars in Star Wars. No more fighters, no more blasters, no more ground troops, no storm troopers or AT-AT's. The entire galaxies' military doctrine would shift to strapping hyperdrives to rocks and lobbing them long distance an enemy home planet. Nothing would look the same!!!!