There is way too much romanticization of a false past here in this larger HN discussion. Yeah, sleep patterns were different, and many people slept with their infants. Infant mortality was also higher, as was maternal mortality, and corporal punishment was common. Sleep-deprived women with piles of children were not spending loving moments staring into their babies' eyes; they were smacking the slightly older children on the back of the head to hurry up and take the chicken feed out and slop the pigs. From my own family histories, I know that babies were often ignored, because at some point having a 1/3 of your babies die means you just don't invest very much emotional energy in them anymore. Very young children were tied to furniture to keep them out of trouble. By age four, some were at work (although the average age to start work in Victorian England was about 10, and the Factory Act came into force to regulate labor conditions for 9-13 year olds). Wet nurses were common, and in parts of England and France in the 1780s for instance it was extraordinarily common to simply ship your baby out to the country so you could work or maintain your aristocratic figure (see references at
https://www.geriwalton.com/breastfeeding-or-nursing-with-wet... for instance).
For my own part, we did some version of sleep training (checking every 5 min until crying stopped). This was overall extraordinarily effective. The reassurance that we're not leaving, we're coming back -- quite important. But as important: the discovery that the child in question doesn't like rocking, bouncing, white noise, or any of the other interventions that are billed as crucial. Leave that kid alone for 4-12 minutes? Asleep. Rock/bounce/white noise? Awake for hours. Why torture the child to satisfy someone else's interventionist idea of good parenting?
Every kid is different. And not every cry needs intervention. This kid cried every time a fart came. At some point you just need to learn the world won't end if you fart, and that is simply gained by experience, not mom or dad rushing to reassure and making a big deal of every fart.