It baffles me that the SK government is evidently incapable of understanding that the issue is wage slavery. Everyone needs to work themselves to the bone, and every single time there’s an efficiency improvement, wages don’t go up and hours worked don’t decline, but “the economy” gets “stronger”. Which most workers don’t actually see any benefit from. So don’t be surprised that your citizens simply don’t have the energy or free time to even consider starting a family.
You can, of course, replace “SK” with many other countries, and the paragraph still works 100%.
A better strategy would be to pull back from late-stage capitalism and find some sort of equitable happy medium between that and socialism that doesn’t also destroy our ecosystem, while maintaining a (small-d) democratic form of government.