...thus, note carefully what Crane is saying here : the ultimate criterion of poetic value is its lastingness, the perennial quality of its beauty and interest.

If true, this should make us revise our notions of literary tradition and development. Not to say that there are not productive advances in literary forms, or that the canon is a fixed collection of past classics. (As Crane points out, Aristotle might have found King Lear a more complex & interesting example of tragic poetry than Oedipus.)

It is to say, however, that beauty is the criterion, which subsumes both pleasure & instruction. The criterion is not merely formal or aesthetic in an exclusionary sense - it's probable that ethical, moral & political values will inform our notion of the beautiful. But poetry also has its own scale of inherent expressive values - originality, elegance, rightness, clarity, eloquence, etc. - which make up the beauty of the work as a whole.

If beauty is the criterion, the critic will have to shun polemics and special pleading of every kind. Claims of novelty, "experiment", marginality, "progressiveness", political relevance, etc., are all partial claims, which - if not related to the final cause and the ultimate criterion (lasting beauty) - actually fall outside the realm of critical judgement.

With these things in mind, maybe readers can begin to distinguish for themselves between general "poetry business" (promotional activities of the entrepreneurial or socio-political kinds), and genuine criticism.