1) We don't know what "knocked us down". 2) We do know that society collapsed, and records of the past are sketchy. 3) We see concept art of derelict human ships, but none of derelict alien ships. (Other than the Traveller.) 4) The damaged side of the Traveller faces earth. The side that faces outward is nearly unmarred. 5) We have received wisdom that the Traveller sacrificed itself to save Earth. But we have no obvious way to confirm this information, and circumstantial evidence that appears to refute it. 6) Bungie has a history of employing nasty twists in their games. (Don't get me wrong, I love that about ya'll.) Salvage is salvage. This shouldn't have too much of a short-term effect, but I'm pretty certain that it'll have longer term consequences. As schisms between player factions, at the very least.