Final answer:
The line from the given references that echoes the comfort in watching a superhero prevent wars or save cities is the one about an untrained hero saving the world.
Step-by-step explanation:
The line that expresses a similar idea to the one from “Why We Still Love Superheroes,” which speaks to the comfort in watching superheroes prevent wars or save cities, can be found in the excerpt that discusses the idea of a hero saving the world and delivering a message that great things await those with genius ideas. This notion aligns with the comfort we find in superhero narratives, wherein heroes like Superman and Spider-Man take on grand responsibilities to protect and serve, reflecting deeply held values such as truth and justice. Particularly, the line about an untrained hero saving the world from the given references mirrors the sentiment of superheroes averting catastrophes and serving the greater good.