>>534952748
In the case of manga and live service games is simply because the vision gets diluted along the years, the plot decays alongside the creativity and motivation of the writer, in the past most novels had decent conclusions because you had to submit your whole novel to an editorial for it to be published, from start to finish, it would only get a continuation if the first book went well, as such, authors actually cared to give their stories a satisfactory conclusion (most likely planned alongside the beginning of the story) because they did not expect to write a continuation for it.