Fantasy often has a few holes in. Take Mordor's representation at the close of the cinematic Rings jaunt - a dusty, arid surface with a bunch of orcs just standing around shouting at each other. Where was the infrastructure? Where did the greenskins do their shopping? Where were the basic sanitation facilities?
Great as Peter Jackson's vision was, it's doubtful he'd ever get a job as a town planner. The same is true of your average dungeon: who, honestly, leaves a big chest full of treasure just lying around next to a badly concealed pit trap? A bloody idiot, that's who.
"Why has someone left that gold?" continues a concerned Simon Bradbury of Firefly studios. "Why hasn't that spider eaten those goblins? Why are they just standing there waiting for me to kill them? I mean, ours is a dungeon with toilets in..."