Whether or not the price different is worth it is obviously up to the buyer.
Imagine knowing that a discount chain is about to make a regular purchase of 300,000 tins of beans. You will happily rebrand, keep it hushed up and take the repeat large orders. It makes me wonder what the margins are on a single tin of Heinz beans.
I remember there was a whole thing a few years ago about fake olive oil and fake grated Parmesan cheese (or what was mostly wood pulp which was allowable per legal definition). I think Kirkland was one of the real olive oil products, but the point is there were differences and some of the expensive brands were real and some were fake.
Bigger brands have bigger pockets to line with profits so we all know that the ingredients are probably the first to take a hit. Discounters do not have to deal with brand taxes.