There are many grim projections for the Cosmic Era, and far from being the most horrific or exotic, the Universe 26 model has a frighteningly real chance of happening.
What if a mage passes his powers on to his firstborn son, and a female mage to her first daughter, leaving the parent POWERLESS? A plain mortal, a sorcerer no longer, all wizardly might gone?
Or: what if a female wizard recieves the power of a mage who sires a child with her? Could lead to promiscuous witches and overly careful mages.