I think there may be a different way to think about it: - the larger a society / civilization. The more specialty it can support - reducing the size of a civi

I think there may be a different way to think about it: - the larger a society / civilization. The more specialty it can support - reducing the size of a civilization can result in a reduction of specialty. - this can result in a reduction of capacity and effectively inflation and a reduction in technology There are definitely other factors as well, but GDP is almost directly correlated to population. A reduction in population is effective a civilizational contraction. If we start seeing a general reduction in population above a certain threshold (idk what that is), you may even see cascading failures. Entire technology sectors are abandoned, etc. which could result in civilization collapse. Arguably, this is similar to what happened in the Bronze Age when the interconnected trade networks failed. Similarly, during the dark ages. Quite possibly we are seeing one now.