We like it or not 1 person in the household taking care of the kids skew the relationship between 2 adults into dependentship as the one working outside perceived to be the one bringing the income (while both should) and the one taking care of the kids and household end up feeling dependent. Some may try to be objective and tell yourself the other one is contributing as much, that is not the way it works in our guts, we like it or not and leads to inequality.
This not optimal for many reasons:
- once the kids are going to school, regular "office hours" daycare is not needed and it skew the relationship even more by removing one task to one party. If that time is used for personal instead of household chores activities, that person not bringing the income is eventually seen as a partial freeloader by the one bringing the income.
- relationship can go sour quickly and if it doesn't work, the "dependent" one doesn't feel as free to end that relationship
- the person taking care of the kid's social life is usually not as rich
The elephant in the room being that in most case it ends up being the woman staying at home in an heterogender relationship in a society with an historically patriarcal model because of income levels which further increase the inequalities and dependentship.
The situation you describe has been happening for most of humanity.
IMO society is worse now with dual income + strangers raising children.
The only major benefits I've seen are 1) Woman have access to birth control 2) Women have equal rights. Everything else is debatable as "better".
I wouldn't call that strangers raising children. Obviously it depends on the amount of hours per day but it is not like you are sending them to boarding school and you only see them during the week-ends.
I also felt that putting my daughters to daycare helped them socially.