Fertility rates can be wildly swung by outliers, and while it is possible to walk with five kids under the age of six, it is a maneuver that requires substantial logistical support or specialized equipment (which can be as hard or harder to store than a car).

https://www.communityplaythings.com/products/outdoor/kinderv... Things like this are 1% or so of the cost of a suburban house! That’s noticeable!