In some other countries family generally takes this role: grandparents look after them

I suppose you've got a point; if the middle class of Americans constantly have their careers destroyed, eventually we'll return to a third world sort of existence where childcare is provided by extended relatives.

However, most people in America can't rely on grandparents for childcare. One reason is we have children much older than people in the third world do - if two generations have children at age 38, it's not very reasonable to be expecting a 76 year old to provide child care.

Odd assumption that everyone has grandparents alive.

Fairly normal if having kids before 20 is normal.

And I suspect disaster to have correlated chances of killing parents or grandparents or children. i.e. if you've become a parent there's a good chance your parents did too.

Our own lived experiences are likely outliers, since developed countries have different outcomes than the past.

> if you've become a parent there's a good chance your parents did too

Crap and nonsense! Rewrite:

Once someone's survived to become a parent, there's a good chance the grandparents survived as well (assuming the norm is to breed ASAP).

Or assumes their grandparents are allowed within 200 feet of any children.