Quote - Incidentally, about changing opinions in art criticism, you will find exactly the same thing in science. A way of looking at things is discarded when a more enlightened way of thinking comes along. We learn as we go. In the 19thC JS Bach was considered to have little merit as a composer. That changed, now he's considered one of the greats. That will never change - there will never be a time when he goes back to being considered third-rate.

Pretty sweeping generalization there.

Take more modern examples with music.   Some of the early rap and hip-hop acts were considered not worthy of musical attention and was largely ignored.  Now there's more appreciation for their work with the popularity of the genre as their contribution is recognized.  But if the genre loses its popularity at some point no one is going to care and they'll sink back into relative obscurity.

So yes, I can see Bach going back to be considered third rate.