Is renaming the instance domain without reinstalling Lemmy related to changing the WebFinger query? It’s the trick some instances use to have a different instance domain from their username domain, like @user@domain.com while the instance is mastodon.domain.com.
No, it’s 100% economics. Why do you think that having “careers, lives and travel” (as if having a family is not having a life?) is more appealing to modern first worlders? Because it doesn’t impact their finances severely. Having more children in impoverished countries is a financial gain because children are free labor and lottery tickets to get the entire family out of poverty. In wealthy countries, children are only a financial loss.