Sure, there weren't many Obsidian Dreadoxes remaining, but that was the case for the high-level Dreadoxes. There wouldn't be much of a point in sending the Dreadoxes that still hadn't acquired sentience. Talking about sentience, in the Werdlem Empire, it was pretty common for that to happen around Stage Five for Demon Beasts. It was very similar to the Mortal Realm of the Lisan Universe.
Of course, there were more stages until a Demon Beast reaches the Transition Realm, Demon Insects in this case. For the Dreadoxes, they kept all those at Stage Eight and below behind.
As for those above this level, around 90% of them were sent out, leaving just a few behind to protect the Dreadoxes' home. It made sense since they always lived in Mountain Ranges where rare Divine Minerals could be found. In this specific Mountain Range, three Space-Time and one Middle Stage Divinity Realm Dreadoxes were guarding the fort.
