This is incorrect. If there are always new collections to criticize, there will always be new discussions IN REACTION to these criticisms, or indeed to the collection itself. For if fashion is nothing but the regurgitation of old ideas with nothing new or noteworthy to discuss in their latest 'manifestations', then fashion is dead, which it clearly isn't. Yet we routinely find in history new modes in fashion - which entails _new ideas_, progress, and with progress, _innovation_.
To say that music criticism is distinct from music discussion and hence that discussion in both music and fashion is "limited" is to misunderstand the history of both. Are you sure that the invention of polyphony, of counterpoint, of atonal music and of sundry new musical idioms - that these are all peripheral to the very discussion of music itself? These innovations have had profound and lasting effects on how we frame discussions in music, how we understand music, what counts as beautiful in music, and for many people, even the very possibilities in music are expanded beyond their limits of prior comprehension. These innovations are not just "new albums" or "new performances", not merely the turning of tricks within old limits. Heraldry, frills, embroidery, women wearing pants, capes, asymmetry, new cuts, bloomers, these are not mere transient innovations in fashion. They affect the perception of what we view as beautiful because they provide new idioms for us to create with. Our appraisals of form, balance, and beauty change irrevocably with the introduction of some of these ideas.
The fact that discussions _here_ degenerate into circularity is not proof of there being limits to fashion discussion anymore than circularity at the local pop music convention "proves" that music scholarship and its attendant discussion is limited. It is to mistake your parochialism for everyone else's.