I'd argue this change has a lot to do with women entering the workforce, to the point most families have (need to have) two working parents to get by. Now what used to be man has factory job woman looks after house and kids is now two parents each have jobs, so who looks after house and kids? Much of housework has been reduced with washing machines, dishwashers, etc.
It's pretty common knowledge (I think?) that in most nuclear households women took on a job and still do most of the housework including child care (especially the mental load - I.e. Keeping track of what needs to be done and making sure it gets done - project manager) Over time men have a started to pick up some of the slack but there's still a long way to go. The article from this post talks about how it's improving for college educated but getting worse for those not college educated.
TBH I have no idea how you count who is doing the childcare at any particular point. If the kids are off playing and both parents are scrolling on their phones, do you both count that time or do neither of you count it, or is there some method of determining who is the primary person at that point? Working out these hours of childcare would be much easier for separated parents 😆
I have said and continue to say that wouldn’t it be nice if both parents could work and support a household financially on 20-25 hours a week each? Both could have careers outside the home and have plenty of time for the rest of stuff, or one parent could choose to work more hours and the other (presumably) choose to be at home like they did in the 50s. But it wouldn’t have to be that way if jobs weren’t automatically 40+ hours.
An interesting tidbit in that article is that the amount of unpaid housework families are doing to raise children seems to be increasing. I wonder what that is about?
This also fits my impression of home life, where there is simply too much work to do for two people, no matter how you split it.