^ I don't think so. The man who stood up to the Necromungers on Helios made it sound like they had their own government and culture distinct from other worlds. Plus, notice that the movie never actually shows space battles--the assault on Helios is atmospheric, as is the rest of the action involving spacecraft. Battles in outer space are fairly impractical affairs, from a real-world perspective; most franchises ignore or work around that, but possibly this is one universe where space battles don't occur.
I'd be curious to see a third film. While I think I appreciated Chronicles of Riddick more for the film it was trying to be rather than the film that it actually was, the ending was unexpected, in a good way, and I'd like to see the story concluded.
Fictitiously yours, Trent Roman