> Japan and South Korea are leaders in sub-replacement fertility with not that much success in finding a path towards sustainable population. Both I believe are

> Japan and South Korea are leaders in sub-replacement fertility with not that much success in finding a path towards sustainable population. Both I believe are still dropping. Straight line extrapolations of demographic trends based on current rates aren't super reliable. The system is sort of self correcting. Once population gets low enough people will eventually start birthing more. The only place it gets to be an issue is geo-strategic, like small populations can just get overwhelmed by larger ones either culturally, economically, or militarily.