If spouse A has earning potential of $300k/yr, and spouse B has earning potential of $50k/yr, and child care costs $40k/yr, it's absolute batshit insanity to take a "balanced approach" and A. lose money on a net-of-taxes basis whilst B. seeing your children less.
Those who don't find the time do be a parent because of work (again, excluding particular jobs) are either workaholics, or uninterested parents, or both; it's not about finance.
To be noted that from approximately the second year onwards (so, I'm excluding approximately the first two), children spend significant hours (whole morning and small part of the afternoon, depending on the parents' choice) in children care. Especially in a family where the mother works part time, the difference from a stay-at-home mom, in terms of time spent with the children, is little (or none).
Fully working = 8-10 hours a day
Still leaves a lot of time for parenting- and doesn’t seem so extreme, I’d say it’s one of the most common division of family life in the world
I didn’t say parenting only takes 8-10 hours. That’s the time the working parent works
That still leaves time to parent when off-work
Maybe you didn't mean it like this... but I find the use of the word "extreme" here in this context somewhat discomforting. Perhaps I'm an old-fashioned 35-year old, but her reasons for wanting to stay home don't come off as extreme to me.