@Will never heard of Dark Forest theory, really cool! I am more biased towards the assumption that trade would lead to a very dark and grim Real Politik among civilizations. If a civilization can eradicate another to take what they need, they will. Except, it's probably better to subjugate for the labor! So at worst you'd have enslavement/subjugation for resource extraction. If a civ can't subjugate through might, then they'd trade at arm's length

@brandt my view is that given the distances, there is little chance of actual aliens showing up to take resources, there are lots of available chemicals and minerals in any solar system, so we would use long distance communications to trade technologies and intellectual property, especially entertainment. Can you imagine getting the equivalent of reels from an alien civilization, I’d trade som nuclear tech for that.