Another possible explanation is if the films deal with topical issues, such as volcanic eruptions, reality television, terrorist attacks, or significant anniversaries, resulting in multiple discovery of the concept.
[4] Mockbusters are usually given more limited release and marketing, intending to take advantage of the public interest in the topic driven by the major film.
Screenwriter Terry Rossio notes that there are always film projects with similar subjects being developed in multiple studios, and that usually only one of them makes it into production in a given period of time, and therefore twin films are better regarded as exceptions to this tendency.
[5] For example, the release of the 2015 Whitey Bulger biopic Black Mass led to the abandonment of a planned film about Bulger that would have been produced by Ben Affleck and Matt Damon.
[7] In one case, for the 1974 film The Towering Inferno, the fear of having competing action thrillers, both set in a burning skyscraper, convinced two Hollywood studios to merge their productions into one (all-star) film.