Angelica: Aunt Didi, what's disco?The polar opposite of Vindicated by History, and a variant on Seinfeld Is Unfunny. This is something — an individual character, an individual song or book or game, an entire genre — that was very, very popular in its day. But at some point, it somehow just got too popular. It was talked about on every radio station, on every TV network, on every chat room (not that they'd been invented then...). It was overexposed until people got bored with it, and it got so much publicity and so many bad knockoffs that there was plenty of time to notice each and every flaw and dissect them under a microscope. Soon, small problems were regarded as unavoidable flaws. The final tell-tale sign is when ridicule, or even hate, comes not just for the thing itself, but for its fans. They become the subject of nasty, highly-specific stereotypes, and gushing about how you like it online is considered trolling. Ten years later, almost nobody will admit that they ever liked it, and the only mention in the media will be cheap jokes about the fad. It may get revived decades later as kitsch, but it's unlikely to be popular on its own merits again. In fiction (and Real Life), a Disco Dan is a rare admirer who refuses to accept the judgment of history and passionately holds on to the belief that the dead thing is still as big as it always was — usually with comical results. Of course, twenty years later, the situation may change again. Sometimes caused by people saying that It's Popular, Now It Sucks too much, but not always: at its height, these people are typically not very vocal. It's particularly common with things that never had a cult following to begin with — they went from nowhere to everything, and then back to nowhere, very suddenly. This is essentially Hype Backlash after something faded from popularity with the haters still remaining. Another cause of this trope, other than simple overexposure, is a franchise doing something that is widely rejected by the established fandom and fails to allow it to pick up a new audience. Falling victim to The Chris Carter Effect or a Kudzu Plot is one of the easiest ways for this to happen, as fans' memories of earlier seasons, films or books are tainted by the realization that the plot that they had spent years following is going nowhere, is being made up on the fly with little forethought, and isn't likely to be resolved. Consequently, the now-former fans tell newbies not to bother. Ending a series on a base-breaking note is another way to do this. In a nutshell, the series enters a Dork Age that it not only never gets out of, but which rubs off on when it was still good. Long Runners may be troubled by changing times (and thus, changing tastes), which can lead entire genres to being not even the shadow of that they were before. Compare Jumping the Shark, Periphery Hatedom, Dead Horse Genre, Fallen Creator, and Hatedom. Contrast Vindicated by History and Nostalgia Filter. If a single work is perceived as rendering something Deader Than Disco, it's a Creator Killer, Franchise Killer or Genre-Killer. Compare and contrast Unintentional Period Piece, when a work can be precisely dated to a specific era, but it may (or may not) have remained popular up to the present day. Not to be confused with Deader than Dead, which is a completely different trope, or Gratuitous Disco Sequence, which is actually about disco.
Didi: Oh, nothing, sweetheart. It's something that happened a long time ago and it's never, never coming back, so don't you worry.
— Rugrats, "Garage Sale" note