Article one already sets Campbell's monomyth against its harshest structural objection, that it selects and abstracts. The comparison sharpens if it is made against a specific rival rather than against the objection in the abstract.
Vladimir Propp's Morphology of the Folktale, published in Russian in 1928 and only widely known in the West after its 1958 English translation, analysed a defined corpus of about a hundred Russian wonder tales and derived thirty-one recurring narrative functions occurring, he argued, always in the same order, though not every tale uses every function. Propp made no claim beyond his corpus and stated its limits explicitly. Campbell's method inverts every part of that discipline: an undefined, worldwide corpus, a single template claimed to fit all of it, and stages loose enough to be found wherever a reader wants to find them. Folklorists have generally preferred Propp's narrower, falsifiable claim to Campbell's broader, unfalsifiable one for exactly that reason.
The monomyth's retrofitting onto specific religious material shows the cost of that looseness directly. A recurring genre of popular writing reads the life of Jesus as an instance of the hero's journey, call, threshold, ordeal, return, and the exercise can always be made to work, because the template's stages are general enough to be mapped onto almost any life narrative with enough interpretive pressure. That a scheme can absorb Jesus, the Buddha, Luke Skywalker and a Grimm fairy tale with equal ease is, for its critics, not evidence of a deep universal pattern but evidence that the template does not discriminate, and cannot tell a genuine underlying structure from a determined reader's pattern-matching.