Such an interesting conversation, I dont redirect to hear such disparate views amongst women, we must move in very different circles.
I'm mid 40s and can only think of 2 of my female friends/colleagues (all in roles likely to be equivalent salary to their DH) who worked FT when kids were younger. One was the main bread winner, the other I don't know the reason but I know she cried most days for the first few months and said she wished she didn't have to. I have other professional friends who went back PT but also said they missed their kids and wished they didn't have to.
It may well be upbringing rather than biology but I do think a lot of women want to be primary carer. The whole 'childcare is more than my salary so I'm sahm' is imo used by those who want to be home with their kids (or who didn't like working).
So I really don't think dropping your career ball will be the primary reason for not having kids. Most (all) women I knew wanted kids and wanted to be the primary carer. Then they may or may not have had shitty lives because of feckless husbands. But my knowledge is I guess 15-20 years out of date, maybe today's 20 somethings do not want kids because they've grown up hearing about the insane cost of nursery, seen how their mothers gave up all their free time to raise them, don't see motherhood as any sort of valued and respected role.
I work with women from Poland. There is a strong push there to get young women to procreate. Asking them to have kids before continuing their education, financial incentives for doing so. I don't know where the fathers in this situation are supposed to come from? Doubt there are many 18 yo men who want to be father's. Maybe a move back to 10 year plus age gaps?