Hollering for help, Lois Lane dangles overhead from a helicopter that has crashed atop a skyscraper. On the sidewalk below Clark Kent, briefcase in hand, squeezes through a panicked crowd, searching for a place to transform into the hero of “Superman: The Movie”, which came out in 1978. He pauses to size up a public payphone, but the booths that served him well in the comic books of the 1940s have themselves transformed, into transparent boxes on pedestals. In a gesture of gentle Kentian consternation, he purses his lips, then moves on. It’s a sly visual joke, in keeping with the buoyant spirit of the film: the world was changing, but he could not—at least, not easily. In retrospect, it prophesied Superman’s predicament in the 21st century, in the existential battle every comic-book hero must wage, the one for cultural relevance.