Anime does not return to school only because its audience recognizes classrooms. School is an unusually efficient social world. Put thirty young people in one building and you immediately have hierarchy, friendship, rivalry, authority, exclusion, performance, and rules everyone understands before the first scene finishes.
That familiarity gives creators room to move quickly. A cultural festival can create cooperation and conflict. Exams turn private insecurity into a public ranking. Clubs produce smaller tribes with their own rituals and status. Even the walk home becomes a space where characters can briefly step outside the roles they perform during the day.
School also places identity under a deadline. Graduation is coming whether the character is ready or not. That makes adolescence more than a stage of life. It becomes a countdown. Confessions, competitions, friendships, and failures feel urgent because the social world holding them together is temporary.
This is where the Japanese idea of seishun, often translated as youth or springtime of life, matters. School stories can romanticize a period when possibility still feels open, even while pressure and conformity are closing in. The setting holds freedom and restriction at the same time.
So yes, school can become lazy shorthand. But the setting itself is not the problem. The question is whether a story uses that miniature society to reveal something about becoming a person, or simply borrows the desks because everyone already knows where to sit.