That's one of those mysteries of life.
Like you said, it's about the money. They use the same cases as for regular cigarette cases, which means they don't have to pay to have new molds made. Cases are a very low profit item for them, since except for the inserts they don't do any of the manufacturing themselves, the case comes from the supplier, and then goes to the printer, and in the end they sell it barely above cost. SO, there's no incentive to pay the costs of making a new case.