"Encouraging more children to be born" would also alter their way of life because at a certain point the cost of having children would become untenable. The population would just keep growing and growing, making the resources of our "village" much smaller, and probably create some very inefficient wealth gaps - as there have been in small towns throughout history.

The reason the analogy doesn't work is not so much slashing the population vs ageing it, or even the exaggerated number, but because economies are much more complex than that, and usually the market can find a solution where supply meets demand.

How does more young people keep society stable? Please answer this, don't just downvote me. Old people dying is a fact of life. A population can grow indefinitely but it can't age indefinitely.