Add a bad luck compensation system. (This is a standard practice, and this system is implemented in many games nowadays. It has 2 possible implementations. #1, after not getting a rare item x times in a row, a player is guaranteed to get one. This system, for example, is implemented in Hearthstone for legendary card drops. Implementation #2: every time a player does not get a rare item, a chance for getting that item gets increased. Such a system is implemented in Rainbow Six for loot boxes. One system is enough, and I like the second one better.)