In addition to women having more independence (although certainly not complete), children too have more independence as they reach adult age. If anything they are pushed out of the house as the modern ideology says that you are a failure if you don’t move out and live your own yeoman existence detached from all ties, familial or otherwise. Capitalism rips apart all social bonds and wants pure atomized workers, and well, that’s what we increasingly see. Mobile and detached individuals with no obligation to anyone.

I doubt many people are consciously calculating this when considering children, but I don’t think anyone would today consider kids as a retirement package because kids have no social obligation to stick around after 18.