Space Opera, once the dominant sub-genre of Science Fiction has declined considerably since The Eighties. The reason for this is two fold. Firstly, the end of the Cold War also ended the Space Race between the Soviet Union and the United States, leading to a period of stagnation. Secondly, around the same time an unexpected explosion in computers and bio-technology occurred. These two factors caused futurists and Sci Fi writters to stop looking at Space for inspiration, and look instead to genetic engineering, cloning, cybernetics, virtual reality, and artificial intelligence, hence the dominance of Cyber Punk and it's derivatives. It's only in recent years, with the over exposure of cyberpunk, nostalgic reconstructionist works of Space Opera (like for example, Mass Effect), and renewed interest in space coming from the discovery of Extra-solar planets that the Genre has begun to recover. Cyberpunk and it's derivatives remain on top however.
For much of The Eighties, the cyberpunk literary genre and movement was the new wave in both Science Fiction and science fact, acting as a fertile seed on a ground tormented by efforts to adapt to a changing world where the computer was king and Japan was the new force on the block. However, books like Neuromancer failed to anticipate how a) the internet, cell phones, personal computers and handheld IT devices would become a mundane reality in the life of the average white-collar Joe Sixpack, and b) that the Japanese economic powerhouse would trip over itself in the early '90s. Once "the future" became the present, cyberpunk went from being high-tech to being filled with zeerust, painting a portrait of the future that had stopped being relevant after about 1993 — the main reason why Post-Cyberpunk came to replace it. Not to mention that the virtual reality craze of the late '80s and early '90s simply shelved itself (for now) after failing to provide a holodeck-like experience.
During the 1850s, there existed an entire genre of "anti-Tom" literature (or plantation literature), written mainly by authors from the Southern US in reaction to the anti-slavery work Uncle Tom's Cabin. Such books were Author Tracts that portrayed slavery as beneficial to Africans, and abolitionists as either misguided idealists who didn't know what they were talking about, or as villains who were lying about the conditions "enjoyed" by slaves and trying to destroy the Southern way of life. For obvious reasons, this genre died out very quickly after the Civil War, while Uncle Tom's Cabin has gone on to be regarded as one of the great American novels.
Pulpy Long-Running Book Series aimed at kids, pre-teens, and teens that were published on a steady clip (sometimes monthly) were incredibly popular during the '80s and '90s, both with story arcs and as standalone anthologies, such as The Baby-Sitters Club,Sweet Valley High,Goosebumps,Fear Street,Animorphs, and even the Spin-Off series The Nancy Drew Files and The Hardy Boys Casefiles. Nowadays, books aimed at children are longer, more complex, and are pre-determined in terms of arcs and book number (Harry Potter had 7, Twilight had 4, etc., compared to the previous series which seemed to go on forever.)
This shift in kid-lit came about in an oddly positive way; namely, publishers stopped believing that Readers are Morons. It seemed to be believed that a generation of children raised on episodic television and music videos would only want bite-sized "episodes" of stories instead of longer and more elaborate books. In fact, one of the reasons that Harry Potter was rejected repeatedly was publishers believing that kids won't read long books. However, after one publisher gave the manuscript for Philosopher's Stone to his young daughter, who devoured it in short order and asked for more, they finally realized that kids could appreciate the depth and texture of longer books, and have been focusing their efforts on finding the next Harry Potter.
...and that was books about "elite" high school girls. Following the success of the film Mean Girlsnote Which could be argued, in hindsight, to be an Unbuilt Trope example of the genre due to its examination of the culture of school bullying., books about the lives of incredibly rich, spoiled teenagers became a big market, with one of the more successful examples, Gossip Girl, even being turned into an even more successful TV series. However, it is very difficult to make these kind of protagonists likable or sympathetic, and the books quickly became Snark Bait among actual high-schoolers.
Gamebooks, which started with the Choose Your Own Adventure and Find Your Fate series eventually evolved into books that actually included combat with Dice. Some books were even published by TSR games (of Dungeons & Dragons fame). Video games can't really have been said to be directly responsible for killing gamebooks but they do provide a non-linear nature that gamebooks can't provide. Also videogames make it harder to cheat, always a spoiler in gamebooks if you turn to the wrong page or intentionally peek at pages that you aren't sent to. And the videogame experience usually promises many hours (even days) of gameplay. Gamebook experiences were notoriously short (as in minutes). The Choose Your Own Adventure books had multiple endings, sometimes as many as 25 in one book. This means that each adventure was rather short. Replay value was somewhat limited to rereading a lot of the same pages, making different choices, and finding different endings, many of which were bad or dull endings. Today, print gamebooks have been replaced by computer based interactive fiction (which could be said to be the Spiritual Successor), and visual novels, although these are more popular in Japan than they are in the rest of the world.
And not just in the UK either; in the US it seems to have fallen into Deader Than Disco territory as fast (if not faster) than its out-of-the-blue meteoric rise from obscurity to the point where it's not even worth being the butt of jokes lest you risk We're Still Relevant, Dammit. Nowadays, the only real mentions if it anymore hinge on who will play Christian Grey in the inevitable movie, with this being attached to every "hot" actor who even slightly fits the bill, from Ian Somerhalder to Matt Bomer to everybody in between, although some, such as Stephen Amell have adamantly said they won't do it, often after actually reading it.
The Clique by Lisi Harrison is the exemplar of the aforementioned "elite high school girl" series and how that genre declined. During the series' first publication run from 2004 to 2011, it was one of the hottest young adult series around, with many comparing it to Mean Girls in literary form (the series started around the same time the movie came out). Several of the books in the series made the New York Times Bestseller List (though frequently for only a week or so), and it received a film adaptation in 2008 starring a then-unknown Bridgit Mendler. Then, almost as soon as the series reached its conclusion, it just about dropped off the YA radar completely, with Harrison quickly moving on to write other series like Monster High and the spinoff Alphas, both of which faded into near-obscurity as well.
Point Horror was a line of teen-oriented horror novels written by authors like R.L. Stine, Diane Hoh, A. Bates, and Christopher Pike that was popular among middle school students in The Nineties, seen as an "adult" version of series like Stine's Goosebumps. They often had pulpy plots based around teenage girls battling psychos, cults, secret societies, and other malicious forces while dealing with high school life, in a manner reminiscent of films like When a Stranger Calls, Sorority Row, or The Skulls, and were never seen as "serious" literature even by the standards of young adult fiction. While there was once a time when Point Horror books could be found on any teen girl's bookshelf, the series died out and was largely forgotten in the Turn of the Millennium (even as Goosebumps and its ilk remained popular with young readers and nostalgic with older ones), and when it is remembered, it's mostly for its Strictly Formula writing.
Douglas Adams and his five book The Hitchhiker's Guide to the Galaxy trilogy. British humor has moved on since then. And a significant number of the humorous references (such as the origin of Ford Prefect's name) have fallen out of date. Globalization has also dated much of the Anglocentric humor. The first two media for Hitchhikers Guide were radio and print, both of which rely solely on verbage. Show, Don't Tell media such as film have had a problem with adapting the works which is one of the main reasons that the 2005 movie failed. Adams' humor doesn't work unless the wording and cadence is preserved verbatim. The later books were less well received and it seems as if the series became a Franchise Zombie. In fact the fifth book is written as though much of the fourth book never happened, (So Long And Thanks For All The Fish was originally supposed to be the final book but was unpopular due to nothing really happening in the story except Arthur Dent's shoehorned romantic interest taking over too much of the book. As well as the fact that Ford is reduced to a background characters, and and Zaphod and Trillian are just written out altogether.). Reportedly, Adams planned to merge Hitchhikers Guide with his less well received Dirk Gently universe. He died before this could happen. Adams had expressed interest in writing a sixth book in the Trilogy would have undone the downer ending of the fifth. His final book, The Salmon of Doubt contained mostly essays and the unfinished Dirk Gently novel that he gave up on. And Another Thing was written by Eoin Colfer in an attempt to imitate Adams' style. This book was met with mostly mixed reviews. For most fans, it's enough that they got at least two or three good books, a radio series, a TV series, and an excellent Infocom game. His social commentary is already assured immortality, and fans are willing to let the series rest in peace with its creator.