Ain't urbanisation made fertility drop tho? Like raising a child in the city is bloody expensive while in the country extra child is spare hands for work

Prosperity doesn't make fertility drop, it makes it less necessary to have children because:

• Parents don't need to have 5 children just for 1 or 2 to survive.. people can have 1 or 2 children and expect them to survive now.
• Adults don't need children to survive. Before people expected their children to help them survive when they are elderly so the kids can work the farm and the grandparents can babysit grandkids in their multigenerational home. Now nursing homes can take care of your needs after saving enough money.
• Now that women are gaining equal rights, they can choose to be other things than just a mother or a wife. Life can be full and satisfying without kids now.

But I do agree people can feel that working and being a mother is too much, and decide not to have kids as well.