I realize these arguments are very common but I think they are more than likely bullshit. Again, I think religious people today are a good proxy for how people were "back then" especially since faith was almost universal.

For example, religious people don't use birth control and have more kids - but it's because that's what they want. To believe that someone has the discipline to adhere to the tenets of religion (eg respecting the sabbath, dietary laws) but keeps having unwanted kids due to uncontrolled lust for his wife, seems bullshit on its face.

The "farm help" thing... I think most people then and now see kids primarily as another mouth to feed in perpetuity, and not some sort of revenue generating asset. Certainly people who have a lot of kids today, aren't doing it for financial reasons.

And when I think back on my grandmother who was one of 5 or my wife's grandparents who were one of 10, it wasn't because their parents were harnessing them to a plow.

People today have kids because they love them, and because they want to cast a vote of influence into the future. I think people in the past primarily had similar motivations. The "farm help/birth control thing" is cope for the childless primarily, no parent actually thinks this way.