loot boxes are designed / deconstructed gambling devices... but also, we see "loot box" design in loads of regular companies too, like when you buy plane tickets or in services where you literally open up a box e.g. Blue Apron
With Blue Apron, the quality of ingredients always ends up shifting... some weeks were terrible, and it was always like "oh, maybe next week's box will be better?" In the end, it always ended up not being worth the price of subscription. I think sometimes they'd skimp on the cost/quality of a box, and then lead you to think that staying subscribed for the next week would be worth it.
Not completely analogous to loot boxes, but I think in both cases the design is still influenced by variable rewards systems, just not as obvious as loot boxes.
I mean, this is a given, right? They can't make money unless the price of the contents + shipping is less than what they charge you.
Although, this isn't obvious at sign up.