No, Mike, I'm not sure I agree with any of that (i.e. your first post/question).
To those in the trenches (in various ways, for various reasons, and to various degrees) I'm sure there seems to be dominant trends and conventional wisdoms that need to be supported or attacked or corrected.
From the outside, though, there seems to be enough room for all, and not much reason for all the rancour. In fact, perhaps never before has what is new and different but still outstanding (in books, music, gca) been identified and appreciated as quickly as it's being today. Meanwhile, what is old and commonplace but still outstanding also seems to muddle along fairly well.
The role of the critic exists, I think, because there have always been, and always will be, people who want and are most suited to being critics. Not that there's anything wrong with that, or that we can't learn much for the good ones. But the actual work (books, music, gca) has always been done in spite of them, and I think continues to be.
Peter