i'm approaching this question from a purely logical standpoint, and nothing else. (i had to place a trigger warning because..people.)
It's actually an interesting question. I personally know a dude, we worked together for a couple of years.
He has 5 or 6 kids with the same girl, less than a year's gap each (still messes around though), doesnt own his own home, and his home is made up of subpar materials. He once said (but to me it came across as bragging) that he was able to save on hospital bills because he took advantage of government sponsored birth clinics.
For context, i'm in Asia, in a third world country. so generally speaking, government run health related institutions are best avoided.
anyway, based on our conversation when i asked him why, it seemed that the difficulties/challenges associated with being a parent hasn't sunk in yet in his brain. That and growing up, even if he was surrounded by poverty, he was always told that having a lot of kids is wealth.(may have taken it literally).
From another standpoint, I was able to participate in a study once about birth rates in provinces compared to cities.
We excluded births from certain circumstances (like if a dude forced himself on to the woman, etc) as much as we could and what we learned was the environment one grew up in plays a big role in it.
For example, not all women wanted additional kids, however, they were not aware of preventive measures nor how to present them to their partners. Same for men: even if they did consider not having kids, they werent taught how to wear a condom or where to purchase one.
Keep in mind, even in this day and age, there are still areas with no signal or internet, so even trying to look it up becomes a challenge.
TL:DR: depending on the individual, some people just accept/think that having kids is something one must have regardless of their financial position.