right now there is basically no requirements from amazon on product packaging. its basically anything you can slap a barcode on. it can be any size, shape, or weight (under the sorting center limit). if it was standardized when received by amazon then it would be way easier to stow, pick, ship these products and automate the whole thing. but one reason i heard is amazon doesn't do this because they can cram way more items in their warehouse he way they currently do it. how do those items get in the standard containers? who knows, that would be up to the sellers/product makers individually, could be robots or human. I mean if they are making the same produc over and over then that part could be automated to put in standard box