Why do we believe that every square inch of the star destroyer is so well planned? Most arguments here assume a design. It could be more "Warhammer" in that the

Why do we believe that every square inch of the star destroyer is so well planned? Most arguments here assume a design. It could be more "Warhammer" in that the system evolved, in a hive city kind of way, making use of whatever was around. A parasite that lurks in the trash compactor would be just the sort of thing a Warhammer novel would introduce and I love that it's there. Wasn't star wars supposed to be a gritty counterpart to high fantasy high space operas? Or star trek?