Fertility rates are currently below replacement, there's no good reason to imagine they will always be that way, particularly after global population numbers peak and fall to, say, half or a quarter of their peak.
What's the basis for your claim? You seem to be saying that people are magically going to have more children because there is a desperate need for them? Maybe if government finances this but how will that work economically at such a huge scale? Will children be born in debt for their birth?
