I remember we learned in elementary school, about three hundred years ago when I was a kid, a correlation (or inverse of) between economic prosperity and demographic picture. It was so obvious it even had named phases for it (that we had to learn, which I forgot).. but from vague memory it was along the lines of expansion (when country is poor), stagnation (when well-fed) and immigration (when rich).
There's a new economic model starting to get popular in Europe called the Donut[0][1] according to which after a country reaches a level of maturity, it should stop focusing on growth and switch to stability so as to avoid overshooting.
