Singletons vs Societies
1. Any society inevitably has internal strife which causes both improvement of its members over time through evolution and cultural transmission & harm through mutual deception, pro-social lies and signalling.
2. A single-entity civilization (aka a Singleton) does not suffer from society-induced issues. However it suffers from isolation and may suffer from memetic ossification.
It is hard to say which model is more suited to the cruel universe in the long run.