You might want to read some accounts of life on lower-middle-class farms, ~120 year ago. Yes, kids were free-ish labor...but basic day-to-day life was incredibly laborious, compared to today. Having kids didn't give you any more land, nor more teams of horses to pull additional plows. Cost of land was not the constraint on the size of your house. Food was not free & unlimited, even in a year with a good harvest. Crop yields were nothing remotely resembling today's post-Green-Revolution & artificially fertilized numbers. Food preservation technology, to have a balanced diet off-season, was home canning and root cellars. The former was highly laborious. The latter had plenty of limitations, even if your local subsoil and water table were ideal for it.