I recall reading that Italy wanted to 'remain Italian', restricted immigration, and offered incentives for their Italian women to have more Italian children.
Meanwhile, social programs, retirement programs need a growing base to support stability, avoid poverty, especially retirees with no assets.
Capitalism and other systems need consumerism.
AI
"The minimum total fertility rate (TFR) required to sustain a stable population in countries with low mortality is 2.1 births per woman. This figure, known as the replacement level fertility, accounts for the fact that slightly more than two children are needed to replace two parents due to child mortality before reproductive age and the natural sex ratio at birth (approximately 105 boys for every 100 girls).
If the fertility rate remains above 2.1, the population will eventually grow, assuming no net migration. However, in developing regions with higher child mortality rates, the replacement threshold can be significantly higher, sometimes reaching 2.3 or more. Conversely, recent mathematical modeling suggests that for small populations to reliably avoid long-term extinction risks from random demographic fluctuations, a higher rate of at least 2.7 children per woman may be necessary."