On the other hand, many container types are already de facto standardized: the lid of the pint of the cottage cheese and the quart of yogurt in my fridge right

On the other hand, many container types are already de facto standardized: the lid of the pint of the cottage cheese and the quart of yogurt in my fridge right now, for example, are interchangeable even though they're from totally different dairies. Milk jugs and cartons are standardized. Cereal boxes, most pop bottles. Instant noodle bricks. The list isn't as long as the list of all possible products, but there are clearly benefits to standardization even in the absence of legislation mandating it.