In the far future, billions of humans may be living off Earth (in a million locations) then it may be practical to have stockpiles on a million asteroids refined from local mines. Transportation of needed construction material is often less costly, than from Earth. Possibly mining robots will be cheap.
The question itself supposes that mankind "must" survive into Eternity, which of course is impossible. Some elements such as gold, antimony, iridium etc are in short supply on earth, and are actually used by the industries of today. There could come a time when mining asteroids is cheaper than any other way of obtaining these elements or of using alternate methods.
Rather unlikely, though.
I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.