Basically every government planned for what has been the norm over the entirety of human history. Which seemed logical up until recently. That means for decades policy and economic decisions were based on the idea that every generation would be equal to or greater in size than the previous one.

The knock on effects of these assumptions are the reason government pension programs like social security are a concern world wide. People are living longer and less people are paying into the systems. This is an issue with nearly all government programs. There are less people paying taxes, paying into social programs. Costs are not going down anytime soon. It’s a recipe for instability.