Often ships sit loaded for months on end (sometimes due to customs or duties / ownership issues). There's also a proximity issue. If a loaded ship is sitting cl

Often ships sit loaded for months on end (sometimes due to customs or duties / ownership issues). There's also a proximity issue. If a loaded ship is sitting close to the states but in international waters, it's easier to get the load back into the states. If you leave the cargo in a storage facility somewhere you still have to pay for the storage, and in addition the transit + time when you actually want to use/sell/offload it.