Film is much more effective than planners or architects at assessing the possible future forms of cities, according to this article from film critic A.O. Scott.
"Architects and planners are by professional inclination both practical-minded and utopian. Their job is to solve problems, to ground their projects in collective hopes for a grander, cleaner, more rational organization of human space. The long-term results of their efforts, however, are typically ambiguous, yielding new problems on top of solutions. For much of the past century, the job of imagining the worst possible outcomes of their good intentions - of assessing the radically dystopian implications of urban progress - has fallen to film directors and production designers. They invent the city of the future not as a model but as a cautionary tale; and their future is the only future we know firsthand."
"To look back at some of those cinematic prophecies is to see the fears and contradictions of modern urban life made visible."