@cjd i think the main problem isn't money.
the main problem is decades of brainwashing that kids are too annoying. that one has to settle first. that one has to "live life" first, glorifying bullshit consumption, booze, weed and being depressed. the messaging that big, multigenerational familiy households are annoying.
it's pretty easy to not think about kids when you take enough s(sri)oma.
If it confers an advantage, rich people will have a lot of kids. If this works, middle class idiots don't have to.
Vance's idea of one vote per child is really interesting, and if gibs are tied to being a "registered non-voter", then these per-child votes are actually pretty meaningful.
I think if you change the culture to where the # of kids = your social status, the problem will sold itself (and in a damned hurry).