And then when the childless people stop doing all of that they are dependant on the children of others (or immigrants!)

Only in the rarest of cases is an amount of individual effort going to out value the benefit of bringing another productive person online.

We really need some sort of immigration platform for sponsorships etc, like why cant I import a few domestic helpers and just feed/clothe/house them.

Basically the only legal way to do that is by having children.