The fact is, when people have the choice, most are showing by their choices that they want to severely limit the number of kids they have, no matter their social, economic, or political conditions. In the modern world, children are seen as a cost, not an asset. Most women in the world today don't want to have 10 kids, or even 2.

In the pre-modern world, kids were seen as an asset, not a liability. Not only did people lack the technology to control their fertility, but kids were essential to survival.