People will start having children again when the world gets their shit together and realizes how serious climate change is and does something about it and how to make an economy that works for all. I get what you're saying and personally it's good the birthrates are down because it's one of the few global signifiers to society that something is fucked up and something has to change. The so called immigrant in problem is the western world possibly coming to grips with the reality of their rampant imperialism.