Eh, nearly all rice that people buy is post-processed to various degrees (brown rice has the outer husk removed, white rice also has an inner layer removed), so manufacturing capacity is also a real concern.

Most rice farmers don't order their rice delivered from a different continent.

Well, they might, but they wouldn't be reselling rice they'd ordered. That would tend to defeat the idea of making your own rice.

More relevantly, it's not at all implausible for a farming operation to be selling rice on another continent, and to schedule shipments several months in advance.