Fan Casting Younger and Hipper in Sort by Tropes

When a work is revamped, relaunched, or reconceived with a young (or younger, at any rate) cast, despite the ages of the characters in the original source material. This happens because it is commonly believed that no one in the audience wants to watch "old people" (defined as anyone over the age of 40 or thereabouts). Often, this happens to supposedly allow Character Development, because the older character has "nowhere to go" and thus making him young again "opens up story possibilities" or, putting it bluntly, just makes him "relevant". Whether or not this is true is open to interpretation.