When the wait simply is not worth it.
Every time the author of a beloved book reveals that the sequel everyone has been waiting for is in the works, expectations begin to swell. However, sequels often fail to live up to the reputation of the first novel. I don't believe that this is necessarily due to laziness or inconsideration on the author’s part; the criteria of a satisfactory sequel are almost impossible to meet! The follow-up needs consistency, character development, and a compelling plot that demonstrates overall coherence. The sequel should be similar enough to the original novel to keep readers loyal, but different enough to justify its existence. Given all the requirements that make for a good sequel, you would think that more authors simply wouldn't bother if a follow-up isn't vital to the storyline.
I often find that books with disappointing sequels would have been complete as stand-alones. Take, for example, Stephen King’s The Shining. As an iconic staple of the horror genre, and more generally of pop culture, it’s assumed that the prospect of another instalment would generate excitement in the public. However, when its sequel Doctor Sleep was released, this wasn’t quite the case. Although The Shining leaves the reader wondering about ambiguous characters and unanswered questions, I personally find that the unresolved aspect of it adds to the story. Leaving the ending open to interpretation fits with the surreal, feverish, dreamlike sensation of the novel; after all, not everything in a haunted house story needs to be rationally explained. Overall, I am of the opinion that the publication of Doctor Sleep, over 30 years after the release of the first novel, only detracted from the brilliance of King's original work by interfering with the mystery of the plot.
However, sometimes, essential questions are simply left unanswered at the end of the first book, and, without a sequel, the story would feel somewhat incomplete. In these cases, brilliantly constructed cliffhangers heavily contribute to the reader’s desire to read on. Sometimes the characters are able to find their satisfactory ending in sequels, but, often enough, events simply lead to yet another unsatisfying cliffhanger in an attempt to string together the plot of yet another sequel. Or even worse, when authors try to satisfy me with frankly implausible explanations, I find myself thinking it would have been better to not know how the story ends at all.
Ultimately, it’s often down to economics. Publishers are aware that if an author releases a popular book’s sequel, people will buy it, resulting in easy promotion and easy sales. Furthermore, many of these sequels can be considered simple fanservice. Fanservice is a product created only to please its audience, without it necessarily adding anything in terms of content or literary value. For this reason, novels that are branded as fanservice are often accused of lacking substance and artistic worth.
Personally, I don’t always see fanservice as a bad thing - I like being able to get another glimpse into the lives of my most treasured characters. However, some sequels diverge from this path and appear to be scoop-hunting by killing off characters for shock value (I’m looking at you George R.R. Martin), in which case fans turn on the writer faster than Annie Wilkes. The key is finding the balance between pleasing fans and writing a novel with a clear purpose, thus avoiding the risk of publishing self-indulgent fanfiction.
I don’t think it’s fair to solely blame authors for disappointing sequels, given how hard it is to write universally acclaimed ones, and just how high expectations usually are. Perhaps we are also to blame in part. We tend to view the authors of our favourite books almost as godlike figures, as beings who were able to create something incredibly special and wonderful and close to our hearts. But the reality, unpalatable as it may be, is that they are just people with bills to pay, egos to please, and absolute artistic liberty over the worlds they create.