None of those things are scheduled so consistently and tightly that they replace an after-school sitter; they mostly make life harder for parents, not easier.

Generally the ideal is co-op; that's what my parents did. I know it's somewhat a radical idea, but you can make friends with other parents. Even with two or three families your individual responsibilities become much more manageable. Each parent can take off early once a week and 7-8 children come over to hang out. You do it right and they won't even really need supervision.

And since you've fostered relationships with the parents of your friends' children (or fostered your childrens' relationships with your friends' children) odds are there will be enough overlap in after-school activities that rides home are equally simplified.

Of course, this sort of stuff does take planning and relationship building, but generally it will be a lot less trouble than having a single-income household.

I'm on a first-name, share-an-occasional-beer basis with every parent on my block (and there are many), and my perception is that this kind of arrangement is not as common or simple as you're making it out to be.

It seems fraught; taking care of someone else's children is a serious commitment. If you screw up your schedule, people lose half a day of work. After-school child care just isn't expensive enough to be worth this hassle.

This isn't meant personally, but from a wide anthropological perspective, I suspect "giving certified professionals money to take care of your children" is farther from the norm than "having trusted friends in your community take care of your children". Just a small aside, possibly worth some thought.