A couple of thoughts triggered by that.  (Not organised as a narrative.)

🧠  The population collapses are well advanced and may not be stopped.

🧠  Japan may turn out to have handled it very well, time will tell.

🧠  I hear that China may have embarked on the worst collapse yet.

🧠  In calculating kids I suggest looking at a single generation only (getting 2.1 kids though!).  Betting on an unknown future may be unwise.

🧠  There is talk of ecological overshoot, I don't know enough to model and estimate that (yet), but I see counter measures in the rewilding movements.  If those ideas are meaningful, then the demographic transition might save the planet.

🧠  I've seen many talk about the problem but not about plausible solutions.  The automation in the Ukraine War suggests that we now have the power to automate cheaply, that will play a role.

🧠  Conventional government economics, and many "models" of society, sometimes seem intent on kicking the can down the road.

(If this doesn't publish right, its my first Nostr post, I will learn!)