If the free market is so good, why are supermarkets still selling unstackable tin cans?

I do like that Pringles cans are 2.5 regular cans tall and their lids fit perfectly on an opened can though - if you want to store leftovers in the fridge. (Not that you're supposed to store food that way but it is handy).I do like that Pringles cans are 2.5 regular cans tall and their lids fit perfectly on an opened can though - if you want to store leftovers in the fridge. (Not that you're supposed to store food that way but it is handy).