In a post awhile ago a sister Miqo'te posted that the major reason for the bad economy was that there was no money sink like there was in the past with melding materia to your equipment. This was because a failed attempt a melding would resort in the destruction of both the item and the materia that were used, which if the process was a success resulted in an item that possibly was better than what would normally be considered better. If what she said was true: then having something like food effects being removed at the start or end of PVP matches or dungeons might help with the economy.