Whilst it may seem that with every passing season there are dozens and dozens of new anime series released, in reality there is a limit to how many animes can be produced at any given time. This limit, unfortunately, has resulted in plenty of popular and critically acclaimed manga’s not receiving anime adaptions and a multitude of equally great anime series not receiving sequels.
The reasoning behind series not garnering adaptions or sequels can vary but in reality, the reasons all stem from three key concepts that being the subject matter of series with how it relates to trends, the marketability of franchise, and the source material itself. Lacking in any of these areas has resulted in plenty of amazing manga and anime never receiving the adaptation or sequel they truly deserve.
The manga world is a cutthroat place since only a small percent of manga see serialization with a large percent of serialized series being based on trendy subject matter it results in most manga not even receiving a small chance to be adapted into an anime. A prime example of how trends influence which manga receive adaptations can be seen with the highly popular series Komi-san wa, Komyushou desu, despite this series being out for almost four years there has not been any solid conversations about it receiving an anime. The series follows the everyday life of a cast of diverse high schoolers focusing on the protagonists Hitohito Tadano and Shouko Komi. The manga does not include any plot twists like the setting being in another world or injects flashy concepts like having Tadano be able to use magic which in the eyes of the uniformed makes it seem like a generic slice of life series.
The influx in the worldwide popularity of anime has created a market where each and every show must have some eye-grabbing elements to hook people in, which has rendered the chance for solid somewhat basic mangas like that of Komi-san to be wrongfully ignored when it comes to what mangas deserve anime adaptations.
Trends like that of having a manga be an isekai have flourished ever since Sword Art Online debuted back in 2012 and saturated the market creating an atmosphere that sees any moderately successful isekai skip to the front of the line and receives an anime within a short time after their debut. A perfect example of this is the series Mairimashita! Iruma-kun like Komi-san it also revolves around following the daily lives of a colorful cast of high schoolers but is an isekai set in the demon world with a main character that uses magical demon powers.
Even though Komi-san began first, is more popular, and is higher ranked, because Mairimashita! Iruma-kun follows the much-preferred isekai trend it not only has already received an anime adaption but also has a confirmed sequel. The power that comes from following trends is something that has robbed great manga from their rightful claim to an anime adaptation, whilst Komi-San maybe the most prevalent recent example older manga like Vagabond or Horimiya have been overlooked due to the favoritism towards trendy subject matter.
Animes also have to deal with the influential power of trends when it comes to them receiving sequels, but something that impacts their chances, even more, is the marketability of a series.
The real purpose of all anime is not to provide entertainment rather they are used as marketing tools in order to sell products, which ultimately means that no matter the quality of an anime as long as it is marketable it will continue to see sequels.
Animes that deal more mature themes or niche concepts are often the hardest to market which rarely sees them gain sequels even if they are popular. Series like Shimoneta to Iu Gainen ga Sonzai Shinai Taikutsu na Sekai or Monster Musume no Iru Nichijou have garnered huge notoriety because of their more adult-oriented contents which should by itself warrant a sequel for either series, but their lack of marketability hurts their chances at one.
Since these two franchises are for a more mature demographic, they are not as marketable to a wide audience and subsequently are not seen as worth the investment by most anime studios.
A franchise like that of Boku No Hero Academia is far more favored since its level of marketability is off the charts compared to that of an ecchi romance comedy. Hero Academia’s wide appeal has led to multiple sequels, video games, tons of merchandise and will continue to do that for years to come.
Anime studios are first and foremost businesses and thus they favor more family-friendly series that they can use to sell merchandise and bring in steady streams of revenues from a variety of places, which leaves Shimoneta, Monster Musume, and a host of other non-family friendly anime out of the conversation in terms of possible sequels.
One of the biggest things that can make or break a franchise’s chances at receiving an anime adaptation or an anime sequel is the source material itself in terms of if there is even enough of it to warrant either a sequel or adaptation.
The world of manga is volatile space and at any moment a manga could stop serialization for a variety of reasons which has proven to impact the chance of an adaption or continuation of highly regarded series.
The coveted basketball manga series Real took a nearly five-year break from serialization which halted its rise in popularity and almost certainly hurt its chances to gain an anime adaption. Real lowered its odds at adaption since the manga is now seen has not having enough content to fully warrant an adaptation.
The chances of Real receiving an anime are now extremely slim since even if a manga is continually serialized it could be years or decades before it can be adapted into a full-fledged anime.
A notable example being Vinland Saga which despite its consistent popularity had to wait over 14 years to garner an anime adaptation. The five-year gap that Real took has forced the series to start from step one and regain the notoriety it once had.
When it comes to an established anime series receiving a sequel the source material is the first thing studios look at since they have to decide if a sequel is even possible. The most notable example of series not receiving a sequel due to a lack of source material is Gakuen Mokushiroku: Highschool of the Dead.
Whilst the series did not gain raving reviews what it did gain was a cult following of sorts which at the time essentially secured its chances of a sequel, but the death of one its creator Daisuke Satou means that the manga will never continue.
The manga itself only has around seven volumes released meaning that there is not enough material for a second season to be created. Most anime are based on some sort of source material and thus for a manga to receive an anime adaption or an anime to get a sequel there first needs to be a sufficient stream of that source material.
Not all manga last enough to see an adaptation and even if they do it is still uncertain if they would continue to have enough for future installments.