I do like a good thought experiment that gleefully ignores the most obvious reason (in this case that stories set is space are not about space, they're about Earth, and all systems will obey Earth logic). What intrigues me about this is it's exactly the sort of thing you would have found in a scrappy Star Wars zine in the 80s or 90s (I myself wrote a long screed defending the existence of Ewoks for a zine that about 50 people read) and yet here it is on one of the big literary journals. The future, eh? Who'da thunk it?

Anyone who had the Kenner Death Star play set knows that it's not a worm. It just has a long neck. Duh.

Perhaps the contractor intentionally created an inefficient trash system? A small act of rebellion, like those that made faulty munitions during World War II.

Christ almighty this scene was the foundation of so many nightmares when I was a kid.

Yes, but isn't the Kessel Run in less than twelve parsecs also implausible, unworkable, and inefficient?