You are assuming that the amount of jobs are zero sum and I don't think we can answer that question. There are situations where there doesn't have to be displacement such as producing goods faster that require more and more people have to sell the item productive.
But, if we would assume that people keep on getting more and more productive due to corporations optimizing for productivity wouldn't we see a drop off of both women and men at the same time? I don't think we would legitimately seem the existing of displacement but actually mutual decreasing.
It might not be zero-sum but someone still has to raise the kids. I'd imagine we'd see dads dropping out of the workforce any time the mom makes more and dad's income doesn't more than cover full time 3rd party childcare.
I was curious about this and looked into it some. Unfortunately couldn't find any source material reliable or concise enough for me to consider linking here - but my overall take on the data is that stay at home dads certainly increased in number, but nowhere near the change these graphs depict.
Numbers vary, but even as of today there are low-single-digit millions of stay at home fathers (under the liberal definition of "18+ male with children in the home who does not work") vs. about ~1m total in the late 80's. Seems like it may account for a point or two on the graphs, but not much more.
Note also that it’s the lower earner’s income after paying the marginal income tax rate on it (when analyzing “what if they quit their job to stay at home?”, marginal, not average, tax rate drives the decision).
For a high-earning couple in a high-tax state, this could be ~50%.
> It might not be zero-sum but someone still has to raise the kids.
In generations past, that was done by women who were counted as not having a job (despite working longer hours than their husbands, 7 days a week). That doesn't need to be the case -- and in fact, dual-income households can create jobs: cleaners, cooks (delivery drivers etc), and childcare. In my grandma's generation, a woman's household duties also included gardening and preserving foods, and making/repairing clothes -- but those jobs have been outsourced so completely that they're now seen as quirky hobbies.
But, if we would assume that people keep on getting more and more productive due to corporations optimizing for productivity wouldn't we see a drop off of both women and men at the same time? I don't think we would legitimately seem the existing of displacement but actually mutual decreasing.