I suspect you are right to ask this question, and have a few items that might point in the direction of an answer. Fuji water bottles are rectangular not only

I suspect you are right to ask this question, and have a few items that might point in the direction of an answer. Fuji water bottles are rectangular not only as a unique branding but in order to economize on space in shipping to reduce transport cost. Large lightweight items cost a lot to ship because they are lightweight and inefficiently use the vehicle. The ideal truckload is a full volume at the maximum carrying weight. So, compared to transporting loads of compacted glass shards, I'd expect that transporting truckloads of empty bottles could be not only high in monetary costs, but also CO2 costs.