Since it would have to be a bag-in-a-box to protect the bag from accidental damage ... it makes more sense to just sell it in a box (carton) or plastic container.
EDIT: Of course, in America the phrase "milk bags" refers to something completely different. LOL
This post was edited by Walt O'Reagun at June 19, 2020 8:43 AM MDT
Bag milk is a scam to get you to buy the plastic pitcher. Actually I miss being able to buy my milk in bags they saved a lot of room in the fridge and it was easy to pour the milk. I still have my plastic milk jug - I use it to water my inside house plants. Cheers!