The worst investment ever

People stopped having children, once the children stopped being potential productive helpers, and had instead been reduced to a financial and personal burden you drag along for 25-30+ years. Bleeding money, time, and energy, but with any later returns going to the Commons.

That's why people increasingly view reproduction as a decadent hobby, where you effectively grow your own pet.

Cats used to work.

That's also why domesticated animals have been reduced to being mere pets: your dog, cat, horse, bird, etc. no longer serves any useful purpose. You are now to serve your pet, rather than the other way around. Pet as pampered perpetual infant, rather than as valuable colleague.

The very idea of a "pet" is a modern outrage. Bring back falconry.

And that's why people who run their own businesses, or live in rural areas, are more enthusiastic about having children. And that is why we have so few children.

Because people think "Can I afford to have children?" rather than, "Can I afford to not have children?"