Europe has done fairly well imho balancing socialism with capitalism and free market mechanisms, good patterns exist today I argue, even if they need tweaks and improvement. Importantly, these demographic curves are locked in for decades into the future, so might as well get comfortable with forward curve of change, we aren't going back to the historical demographic growth curve in anyone's lifetime, if ever. Plan, forecast, and model accordingly.

The demographic future of humanity: facts and consequences [pdf] - https://news.ycombinator.com/item?id=44866621 - August 2025 (400 comments)

(~71% of the world’s population now lives in countries with birth rates below the replacement level needed to maintain population size, the remainder will follow in time)