(If you change the rule that everybody dies exactly once, the 1:1 ratio changes, but what happens to population dynamics when you mess with mortality existing AT ALL is a whole nother rant. And something people screw up even more.)

Can I just step in to say, I've been fiddling with the math for this for quite a while and it is so fucking frustrating? I hope you do decide to post about that, because it's been giving me fits. The closest model I've got is a population pyramid with a loooooong tail, and it ends up mattering immensely how old the population is (it's hard to get an equilibrium when death is rare and optional), and it just all gets very complicated. On the one hand, if death in battle or childbirth or plague is too common, it makes it very, very hard to get enough children to replace all the young adults who, after all, are exactly as likely to die as are any other group, and yet if it's too uncommon, the population grows out of control.

(And it's hard to wrap my brain around what a family unit even looks like in that kind of society. Can you ask your eighth-great grandchild to babysit your youngest for you? I have no idea. There's no real-world precedent there, I guess.)

So yeah, I don't know if you know any more about that than I do, but it certainly is complicated.

(Also, thank you for this post!)