gamerprinter
Mapper/Publisher
The module - however it is written - is static. It can't adapt. So it either leaves things for the GM to decide, or forces the plot. When too much is left for the GM, there is no gain from using a module (books and movies work better as inspiration). When too little is left fluid, players like me go off the rails and the module just doesn't work.
Maybe there is a module that hits the narrow line between the problematic cases and offers fun experience. But I never met such these I played in. And my time became too limited recently to risk wasting it trying any new modules.
This is true with every module. If you look at The Curse of the Golden Spear trilogy of modules for the Kaidan setting of Japanese horror, for example, especially the second module and third modules, Dim Spirit and Dark Path. Boxed text provided throughout the module make suggestions should the party not follow a particular road or direction, how certain encounters can be relocated and what options GMs can take to maintain the storyline. The adventure writer understands that not every party will follow the same path.
Not every module is static.