Meh on this as sure, children require a lot of energy and investment but how are they MORE a burden now with modern agricultural technology able to do the work of 100 people with 1 person than back in time when everyone worked or starved and childhood didn't exist.

You're looking at it at a societal level. You should look at it from an individual level. On a farm, a kid is used to help from an early age, and more kids means more security in retirement - as the norm is that kids take care of their parents when they are old.

Right now, a kid only costs you stuff. You have to pay exorbitant sums on everything from food, clothing to college tuition. You have to forgo vacations and get a babysitter (who may be molesting your kid) whenever you're away from the home, so you don't have any freedom. And this for what? Certainly not for any tangible financial or other sort of material benefit. While that is not all there is to having a kid, it certainly doesn't help to have the material costs be so onerous.

Relationships are a Legacy as you think of power couples or with grandparents staying together for decades creating several generations. Now , it's all instant gratification to the extent that kids are a burden to having more fun.

But I know people who have stayed together for a long time without having kids. So like I said, there's more to it than just that, though the 60s culture definitely does not help.