I once worked a temp job for two weeks with a company that manufactured lights to mount above snow plows. (Once you mount one on a pick up truck, the original lights are blocked.) All the same parts, made by the same people, the only thing that changed was the packaging. They made them for all the store brands, name brands, what have you. If one company ordered a recall because some of them weren't wired right, every other company may as well do the same.
I know someone who worked for a company that made generic drugs. One day they would put the pink dye in the vats and the oblong pill press and one type of bottle on the conveyor belt, the next day the blue dye and the oval pill press and another type of bottle on the conveyor belt, the next day the yellow dye and the round pill press and another type of bottle on the conveyor belt. That it was all the same formulation of say, acetaminophen didn't matter. One was for the large chain of pharmacies, the other was for the name brand, the other was for a department stores own brand.
It's lovely to think there are dozens of say shampoo factories, or battery factories, but the truth is that often there are just one or two. They make products for end retailers. That it happens to be exactly the same product, isn't relevant. The end seller can charge what they like.