Um, no? First of all, there are quite good books on the movies. Read Star Wars Episode III: Revenge of the Sith by Matthew Stover. Secondly, the problem with game/movie novelizations and book/game adaptations is not the superiority of any one art form, but that they require a slightly different perspective in creation and their key techniques are integral to the quality of the work. Well, and the fact that novelizations are often not written by professional writers.
Thus, books use imagination, and one of the reasons books are popular is to create images of characters and places in the reader's mind, which is often seen in the way fans are disappointed in the cast of actors, because they do not correspond to the sum of the images in the reader's mind. That is, personal perception is an integral part of a quality literary work and the attempted "forced" rendering in screen adaptations often spoils this effect.
The main element of cinema, accordingly, is the audiovisual component, including the nuances of camerawork, the selection of lighting to match the mood of the scene, etc. A quality novelization can retain some of these impressions through good literary language and the conveyance of mood through the descriptions and thoughts of the characters and the small details in their actions.
The most indispensable element of games is obviously their interactivity. The player is directly in the midst of all the events and his actions somehow have some effect on the world around him, which multiplies the immersion in the action on the screen. When creating a novelization/movie adaptation, the author is limited to choosing certain actions, certain paths, so often other characters are chosen as protagonists, which may simply not interest fans, because they do not have the same connection that is established with the protagonist of the game.