I'm sorry, but is Miles Morales really that popular? I'm sure he's a cool character, but does your average joe who sees CBMs but doesn't read comic books know who he is? Never mind the movie facing both a SH movie (Aquaman) and a family movie (Mary Poppins, though I admittedly am more optimistic on its box office than other predictors.)
http://collider.com/dwayne-johnson-jungle-cruise-movie-patty-jenkins/
Not a confirmation, but Dwayne Johnson really wants Patty Jenkins to be the director...yeah, I'd be down with that.
I doubt there will be fatigue, outside of one underperforming film here and there, but 2018 definitely feels like the peak for SH box office gross, at least within the next few years.