Carrol, your point is well taken. Robert Bly's Leaping Poetry, an ostensible presentation of the value of unlikely juxtapositions in poetry, includes many poems that seem only hodge-podges of imagery. Anyone can throw unexpected combinations together; take one from column A and one from column B and voilà -- soluble fish!
While abrupt juxtapositions without accompanying label of their point
are prominent in much 20th-c writing, it is well to keep in mind Pound's
warning (paraphrased from memory) against any old rotten cabbage thrown
on any fine silken couch. There is, for example, a certain
tongue-in-cheek quality to Pound's lines in Canto VII --
"Beer-bottle on the statue's pediment!
"That, Fritz, is the era, today against the past,