With all due respect, you sound like someone who doesn't have children. Most of the argumentation for "parents should stay at home and care for their kids" is based a different world to the one we now live in - a throwback to times where we lived in small communities and child raising was more a group effort with grandparents and relatives helping out.

Today 56% of the worlds population lives in cities. That means childcare is essential for socialising a child.

A child at home with a parent until kindergarten is probably going to spend the first 4 years of their life in a small apartment with one adult, bearing in mind that many young parents are generally not well off. This is not healthy situation for the child or the adult.