->''In a closed system, any process that occurs will tend to increase the total entropy of the system as time passes.''
-->-- ''Second Law of Thermodynamics''
It's not just that all things must come to an end, but that the longer that series, books, and games go on, and the more changes they undergo, the likelier it is that something will get lost as time goes by. For example:
* SeasonalRot (aka Season Decay)