Yes, Dead Orbit has so far been useful. They're using their fleet to provide valuable intelligence to the Vanguard. Here's the problem though, their endgame is we abandon Earth and aggressively expand across the stars until no single threat can hurt us. While not a bad plan on paper, we know for a fact that this plan is a dead end for us. Even if we had the men and materiel for this undertaking (we probably don't), the plan is impossible long term. The very philosophy of the Darkness demands our extinction, and it has consumed civilizations many times more expansive than Dead Orbit can even begin to dream of. It can't be outrun. The only entity with even the slightest chance of beating it back is the Traveler. Where's the Traveler? Why, it's sitting in a coma over Earth, the planet Dead Orbit wants to abandon.
English
-
Actually, even the races that were previously with the traveler and the darkness managed to travel across galaxy (maybe even universe?). We see that in the Fallen and Cabal. The technology exists in the game, even if we need to take it from another racr. Hell, the tech for manipulating time exists, so anything is possible. Combine tech for space travel with time manipulation and it would be possible to travel the universe in a matter of seconds.
-
The Cabal have act silly never encountered Love thy or Dark before our system. Their sole purpose for being here is a he study of acquisition of Vex tech. The only reason the Fallen haven't been completely wiped out is that with the Traveler so close the Darkness hasn't bothered finishing them off yet. They are the singular exception though. The only race to ever process the Traveler who don't any longer and are still alive