The survivors in B would eventually catch up with the living population of the world today, yes. However, the survivors in B would never catch up with the cumulative population of the universe where there was no catastrophe. While the survivors in B were recovering, the counterfactual universe has been creating more humans (as well as new pieces of art, scientific discoveries, etc.). It is impossible for B to catch up, regardless of how much you wait. All the human potential of the 99% who died in the catastrophe is lost forever.
It’s true that the universe B might never fully catch up because 99% of a single generation was lost. But over 1 billion years, we would expect about 40 million generations to live. Even if a few generations were lost, if there is a recovery the total loss won’t be high.
Whether and to what extent the survivors could catch up with the counterfactual universe strongly depends on the boundary conditions. Universe A could have expanded to other planets by the time B fully recovers. We are comparing the potential of a full, and fully developed humanity with a small post-apocalyptic fraction of humanity. I agree with you that planet boundaries (and other physical constraints) could reduce the potential of a random 1% in A with respect to B. But I suppose it can also go the other way: The survivors in B could produce less humans than any 1% of A, and keep this trend for many (even all) future generations. My intuition here is very limited.
The survivors in B would eventually catch up with the living population of the world today, yes. However, the survivors in B would never catch up with the cumulative population of the universe where there was no catastrophe. While the survivors in B were recovering, the counterfactual universe has been creating more humans (as well as new pieces of art, scientific discoveries, etc.). It is impossible for B to catch up, regardless of how much you wait. All the human potential of the 99% who died in the catastrophe is lost forever.
It’s true that the universe B might never fully catch up because 99% of a single generation was lost. But over 1 billion years, we would expect about 40 million generations to live. Even if a few generations were lost, if there is a recovery the total loss won’t be high.
Whether and to what extent the survivors could catch up with the counterfactual universe strongly depends on the boundary conditions. Universe A could have expanded to other planets by the time B fully recovers. We are comparing the potential of a full, and fully developed humanity with a small post-apocalyptic fraction of humanity. I agree with you that planet boundaries (and other physical constraints) could reduce the potential of a random 1% in A with respect to B. But I suppose it can also go the other way: The survivors in B could produce less humans than any 1% of A, and keep this trend for many (even all) future generations. My intuition here is very limited.