The culture of twenty-first century Earth had become such that “cults” were liable to spring up around any sub-popular or limited-interest literature. These weren’t cults in the typical, ritualistic sense; rather they were groups of (usually) like-minded people who defended their literature to the hilt, in the face of opposition from those who saw these pursuits as trivial, or worse, abnormal. However, the accumulation of concurrent beliefs among a group entrenched in a fiction, and thus feeding back into that fiction, easily led to an over-reliance on cliché.
As the members of these cults sought approval from their peers, so the concepts intrinsic in their fictions homogenised. Thus, as every member of the group tried to please every other member of the group by including in their fictions that which they thought their entire faction desired, no-one was able to produce anything truly original, for fear of upsetting a sizeably vocal portion of the group.
These portions somehow between them created a desire for everything to comply with everything else, when previously this had not been a concern. The increased reference to this overall “canonicity” quickly transcended the cult, becoming an enemy to creativity of its own without actually possessing any substance beyond a purely memetic existence. Soon, it had pervaded the culture on so many levels that it became entirely impossible to produce a story in its own right, as any such story would in its composition contain so many elements that had previously not existed that the story itself could not fit in with the established elaborated universe (at least, not without referring wholly on previous ideas published possibly forty years ago). Idea was quickly replaced by cliché as everything conformed to the stereotype, anything even remotely interesting went out of the window and mankind became like a string of sausages, each one thinking exactly the same; no-one daring to rebel.
Of course, what no-one seemed to realise was that the new created universe didn’t actually exist and could therefore bend to fit whatever constraints it required. For if the stories that were created were of sufficient quality and interesting enough for the cults to enjoy them, then they’d find a way to include them in their universe anyway.