What are some possible reasons for people writing bad books in the fantasy genre?

Self-publishing has lowered the barrier of entry, so it is possible to publish with little to no writing experience, but I would say that has increased the number of good and bad fantasy books. There are authors who wouldn’t get traditionally-published for reasons that have nothing to do with their skill or talent, who are able to publish via self-publishing. Of course, there are also writers who are not good at writing who publish this way as well. That said, traditional publishing has given a platform to many terrible books, so I think this is just a quantity thing rather than self-publishing selecting for bad books or traditonal publishing weeding them out.

Fantasy is a large and popular genre compared to some smaller genres or subgenres like “military science fiction” or “family sagas” so if you are looking at “fantasy” as a genre you are looking at multiple successful subgenres at once. Of course with such a large pool to draw from, it will seem like there are more bad books than in smaller genres because the sheer volume is so large to begin with. If you looked at separate genres of fantasy (high fantasy, low fantasy, urban fantasy, historical fantasy, YA fantasy, MG fantasy, mythology retellings, science fantasy) and looked at the ratio of good:bad books in each subgenre using whatever metric you want, you would probably find that some genres have more high-quality writing, or that you just like the writing styles of some of the genres more than others, which is fine. I’m not sure how you’re defining a “bad book” here, though.

Also, what “pool” of books are you looking at? Bestsellers, award winners, stuff people are talking about on Reddit, BookTok hits, what your friends are reading, any traditionally-published fantasy, self-published fantasy, or all fantasy as a whole? A big part of the reason I think people have a hard time getting into reading is that book communities on social media tend to act as if a relatively small “pool” of books is all that’s out there and all that’s worth reading. YouTubers will often focus on new releases or things that are already popular rather than a variety of books that are representative of the fantasy genre as a whole, so people who don’t like whatever is popular at the moment or whatever is considered “classic” may decide the genre isn’t for them. Even outside of social media, a lot of what is marketed heavily (bestsellers, celebrity book club picks, whatever the airport bookstores have these days) just isn’t to people’s taste, and people who don’t know a lot about books and don’t have much time to look into what they are interested in are going to assume that’s all that’s out there. If you looked at fantasy in a subgenre you particularly liked, you might find more that you consider “good” because it interests you.

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I think that in fantasy specifically, there are a lot of bad books that use the same fantasy elements the author liked in Lord of the Rings, Game of Thrones, Harry Potter, or anything Brandon Sanderson and Neil Gaiman have written. Since a lot of fantasy’s appeal is dependent on certain tropes, using common fantasy tropes doesn’t make a work inherently bad, but when an author doesn’t have the skill to make a good story out of them then the final product doesn’t really stand out.

Every genre has its share of bad books. Fantasy is no exception.