I was at a Kellogs plant down in Mexico last year. They were using massive amounts of manpower to put the child boxes into shipping cartons.
I asked them why don't they have machines doing this? It'll save on their ridiculous manpower and clean the place up.
Their response was that the manpower was significantly cheaper. So cheap that installing new machines would almost bankrupt the place.
Also in some instances, it has to do with power supply. Some facilities can only run so much amperage before causing these poorly built power grids to collapse and in turn cause a cascading effect toward other similar power grids.