Think the west is any different? Canada also hovers at round 1.3. (https://nationalpost.com/opinion/canadas-birth-rate-has-dropped-off-a-cliff-and-its-because-nobody-can-afford-housing - just sourcing 1.3, I don't actually agree with their reasoning) Canada's population only increases because of massive immigration they accept. And immigrants from poorer countries are more likely to have children than existing. So, might even rival SK if we were to not count 1st/2nd gen immigrants, though we don't have such exact data collection, only corollary.
I see what you’re trying to say but immigration simply is an important part and especially feasible for huge countries like Canada. Good luck on getting proper immigration programs up and running in SK, Japan or especially China though. Foreign workers are of course at an all time high in Japan, but it‘s not on a western level and the push back is fierce there as well. The stigma there is on a whole different level, making immigration especially uncomfortable.