I get the impression it is general inventory management.
FFG produces a ton of other games, and they don't seem to have the same problems with keeping stuff in stock that X-Wing does.
If it were general inventory management, than Game of Thrones LCG, Netrunner, Star Wars LCG, Decent, Rebel Assault, ect... would also all be having issues with keeping product in stock.
Having worked in the printing industry in a small shop, I can tell you that printing cards does not take long.