Walmart used to be (and maybe still is?) known for doing this. They would get companies to produce lower-quality versions of products under the same name as the standard versions available elsewhere. They could sell them for cheaper and consumers were none the wiser - or so the theory went, anyway. Obviously people caught on.
I've noticed this at Aldi too. Boxes of muesli that look 30% cheaper than at other supermarkets... but when you look closer, the box is 3/4 the size and it's only 3/4 full. I don't regularly shop at Aldi.
