Here's an example I remember from some Vinge novel ("A Fire Upon the Deep" maybe) I read decades ago: some ancient species/entities were supposed to have transcended a long time ago. What did that transcendence consist of? Where did they go? What's their life like after transcendence? Vinge gives the reader nothing. I call that a failure of the imagination.

Yes, I get that the post-singularity world is supposed to unpredictable/unimaginable in principle... but it's the author's job to imagine it anyway, else why am I even bothering to read his books on the singularity? If he doesn't/can't imagine it, I judge it a failure and a disappointment.

I don't remember details about Egan's work, except that nothing in it seemed particularly interesting and nothing wowed me... hence I really can't remember much about it except the premises of some of his novels, like Permutation City.

This is contrary to works by authors like Gibson, Herbert, and Dick, for instance, which I'll never forget. They're just leagues ahead of lesser authors like Vinge and Egan.