One of the then, common comebacks for similar pocket items was the Stone of the Tortoise but we were told at that time, the Stone did not pay for itself and it was a complete loss leader and that the Stone was created for other reasons. Now, that the Stone has been on sale and gotten some more "push" perhaps it is now profitable.
You can do this today by doing any of a number of things like removing armour, stop leveling for a bit, no food etc. without spending any developer time to make something and apply it across the board so that it works everywhere properly. If developer time is allocated to something a player already has control of themselves that means less developer time for other items.
note: developer time would include all the departments that would be affected by creating such an item. It's not just one developer, it's the whole front and back end.