and therefor you will not be surprised to find out that there has been a very recent dramatic decline in the asking price for empty containers in areas that are primarily devoted to imports, as the empty can is not worth the cost to ship it back.
We should standardize some "dual-container" format that can be formed out of disassembled containers.
In this case it's because of the time it takes to load the empties because its more profitable to use the time sailing. Some ports have rules now forcing them to take back empties so the yards don't fill up.