Whether it was a rushed ending or a story that did not have illustrated material or was just novels that had true hardcore fans but never had tools or the mediums where fans can demand works to be created or extended as anime. Black Blood Brothers is a great example where the anime had a good fanbase but the studio decided they would not complete the story or bring it back for another season despite many efforts from fans via signed petitions and social media posts, 18 years later and fans requests still fall upon deaf ears.
Web3 tools and frameworks could stop this from happening again and even ensure superior quality of product. Imagine if fans had the capability to partly fund a season and interact with the creator and studio all while having contingency plans for the intellectual property of the manga/anime and some of them even have a vote that affects the creative process of which the elements of the story take place and when the product comes out whether its a season or merch or game or even a toy line they get paid out some royalties and have exclusive access to other perks as true early fans; all in one smart contract ( code that acts like law and cant be altered or destroyed and lives forever on the blockchain).