You're focussing primarily on PRODUCERS here. The main focus should be AUDIENCES and how they interact with the production/distribution/exhibition complex.
Gothic fiction, sometimes referred to as Gothic horror, is a genre or mode of literature that combines elements of both horror and romance. Gothicism's origin is attributed to English author Horace Walpole, with his 1764 novel The Castle of Otranto, subtitled "A Gothic Story". The effect of Gothic fiction feeds on a pleasing sort of terror, an extension of Romantic literary pleasures that were relatively new at the time of Walpole's novel. Melodrama and parody (including self-parody) were other long-standing features of the Gothic initiated by Walpole. Horace Walpole's The Castle of Otranto (1764) is often regarded as the first true Gothic romance. Walpole was obsessed with medieval Gothic architecture, and built his own house, Strawberry Hill, in that form, sparking a fashion for Gothic revival. His declared aim was to combine elements of the medieval romance, which he deemed too fanciful, and the modern novel, which he considered to be too confined to strict realism The basic...
If a film does sells very well and gets high praise from the audience and critics and there is a suitable plot or story to a sequel then the producers may decide to make another movie because they know they will make money from it because the audience will be keen to watch it too see if it is as good as the first one and so forth