Does anyone here genuinely think interstellar civilisations are possible?
Trade ceases to be possible, as nothing is easier to move between star systems than it is to make locally, as no human labour is needed to produce; only raw materials
Communication is slow, causing great cultural divergences between star systems.
Weaponry is apocalyptic. Even a mishap with automation could be apocalyptic.
The way I see it, colonies in different star systems have:
>no practical reason to cooperate with each other, trade is meaningless
>no feelings of loyalty or goodwill towards each other, they can barely communicate with each other
>a practical reason to wipe each other out (the only valuable thing is sheer quantity of the elements you need)
>ridiculously powerful weaponry that can hit without warning and prevent a retaliation through sheer sudden damage