A civilization with the kind of industrial base and know-how to build Dyson swarms probably also has the ability to create smallish self-sustaining colonies, in

A civilization with the kind of industrial base and know-how to build Dyson swarms probably also has the ability to create smallish self-sustaining colonies, in space or on/within uninhabitable planets. With enough of those floating around, even if most of civilization was wiped out, it seems likely that someone, somewhere would survive... and potentially be able to reseed a future civilization. So there’s hope.