Deader Than Disco/Anime and Manga

For anime and manga series and trends that are nowhere near as big as they used to be.

Anime & Manga

• There was once a time where every anime fan had to have at least seen one episode of Inuyasha. Every con would at least have a dozen people cosplaying as the title character. Hell, it occasionally leaked out of the anime fandom and it wouldn't be uncommon to see people on the street wearing merchandise from the show. Nowadays, the show's largely considered a joke that most newcomers would never dare to touch. This is likely because of the frustration amongst fans of the anime watching it for years only to see it end without any conclusion to any of the plot. By the time a conclusion was reached with The Final Act, the damage had been done, causing lots of fans to simply tell newcomers "not to bother with it" or "read the manga instead".
• Poor, poor Fullmetal Alchemist. Once hailed as an absolute masterpiece the likes of which the west had never seen (even gaining a lot of mainstream popularity with those who otherwise weren't anime fans), word soon got out that it *gasp* wasn't completely faithful to the original source material! After the release of the direct manga-to-anime adaptation, Brotherhood, the fandom shifted from praising the first series to blasting it for straying from the manga halfway through and proclaiming Brotherhood to be far better solely because it follows the manga.
• Bleach started off as an overnight sensation, gaining rapid popularity in Japan (and in the anime fandom in the West) to the point of being considered one of the "Big 3" of Japan along with One Piece and Naruto. Around the time of the Arrancar arc however, Bleach suffered massive Hype Backlash due in part to it's rather infamous reputation for Arc Fatigue. Said Arc Fatigue also negatively impacted the anime, as well causing (multiple) lengthy filler arcs. To add insult to injury, declining ratings would lead the anime to be unceremoniously cancelled and replaced by a Naruto spinoff. These days, with impending ending to the manga as well, most of the fandom had already called for Toriko to replace Bleach as part of the Big 3, which itself didn't work. This was somewhat subverted when an anime adaption of the last arc was announced, though we'll have to see about that.
• Mobile Suit Gundam SEED was once a smash hit, getting the second highest ratings in Gundam history only behind Zeta Gundam, and introducing a new generation to the Gundam franchise. Fans would start clamoring for a sequel, which they got with Mobile Suit Gundam SEED Destiny, the first-ever full-length television sequel to a Gundam show outside of the original Universal Century timeline, as well as a manga spinoff in Gundam SEED Astray. There were even talks that the CE timeline could become the new UC.

However, thanks to troubles behind the scenes and the like, Destiny failed to be as successful as Seed, evidently ending those talks, and heavily dividing the fanbase in the process. There were plans for a movie to be a Grand Finale of the saga, but the head writer was fighting cancer (which is partly the reason Destiny had such issues) and to this day is in Development Hell. This made both the creators and the fans give up on the saga and move on to the non-CE series Mobile Suit Gundam 00. Today, if you ask Gundam fans of their opinion of Seed, you will get plenty of Love It or Hate It responses, and you certainly won't find many fans of Destiny.

• This trope was referenced once in the English dub of Digimon Adventure:

Demidevimon: Aw, come on! Everyone makes mistakes, remember disco?

• Love Hina has recently caught under fire thanks to Values Dissonance as a result of playing Double Standard Abuse (Female on Male) for laughs with its main protagonist Keitaro.