In fairness, there's a big difference between

• Building colonies when you come to fertile land in large numbers organised specifically to build new societies, where you get to pillage tons of local resources and slaves with your superior tech. Food and edible animals grow everywhere, freshwater is plentiful and threats to human life are relatively few.

and

• Rebuilding society in small, disparate and poorly prepared numbers, almost certainly ravaged by madness, injury and/or disease. Every other square metre gives off lethal radiation, or hides poorly understood tech, creatures, robots and mutants that will kill you in a heartbeat even if you are a hardened adventurer. Every other room is filled with ammunition and explosives that aren't hugely conducive to rebuilding society but are conducive to dying more. Fruit and game grow practically nowhere, and a massively enhanced amount of effort needs to go into growing any kind of crop or harvesting any water that is even slightly suitable for consumption.