Now that the golden age of the blockbuster superhero-comic-book movie is supposedly—and thankfully—over, fans of last decade’s Marvel and D.C. pictures should be demanding more, not less. Will there be rioting in the streets once audiences get some idea of how lousy Supergirl is? Probably not. At the screening I attended, a trio of good-natured fanboy-slash-influencers sitting behind me—before the movie started, they’d been chattering loudly about comic-book-related entertainments they’d either