Generally speaking countries that have tried to do something about their abysmal birth rates (Hungary, Czechia, etc) by putting in substantial economic incentives (i.e. 4 years of maternity, free accomodation, etc), have found that it moved the needle very little and certainly there can't be much talk of reversing the trend.

Also, I believe that our culture of over-parenting (and therefore many of the associated costs) is a _consequence_ of having fewer children, not the cause. If you put all your reproductive eggs in one basket, you are motivated to overprotect them. That makes a culture of (at least from a historical perspective) insane parenting demands that simply don't scale.