I still don't understand how so many people used to be able to afford having so many children, but not nowadays. Was child-rearing just less expensive back in the days?
Parents weren't giving their kids a gilded childhood. Children worked. Having more children meant more help with the farming, housework, etc., and/or they could work in coal mines, as chimney sweeps, etc. And also most kids didn't go to college back then and got married off young, so the parents had less financial burden. Plus the cost of living was a looooot more reasonable in comparison to the average household's income.
Also, once the first girl is old enough (like 6) she can take care of the other kids so you don't really have to do anything except to keep making them.