They were about sitting in a movie theater when Kennedy was shot, or about looking at a painting of the resurrection of the body. She also came in the wake of feminist descriptions of the relations between the sexes which had, by and large, cast men as oppressors and women as victims. In these ways, she has been original. It has waned, in part because the field of literary study has moved toward attracting students to literature as a mirror of society, rather than literature as a perfection of a certain medium. If you think of poetry as the perfection of the use of language imaginatively reconceived, then it is of less interest at this moment because perfection is not what the study of literature is currently organized around.
Perfection is thought of as attainable by very few, which is true.
There are only four or five voices in a century in any given country which remain living voices after the topical interest of their verse has gone. This small number of survivors judged on originality doesn't appeal to a democratic culture. The status of poetry has, for the time being, gone down. I believe that interest in the study of literature almost always goes back and forth between text and context. Then that intensity died down and interest in the text itself, especially mediated by psychoanalysis, became very strong.