It holds the lofty perch of being the greatest cinematic achievement of all-time. The American Film Institute picked it as the best movie ever made. Twice. François Truffaut filmed himself daydreaming of Orson Welles in Day for Night (1973). Liev Schreiber starred as Welles in an HBO movie about the film’s making. Citizen Kane is like the white whale for moviemakers who want to make movies about other moviemakers. And now David Fincher is giving it a singular, and possibly revisionist, angle in Mank, a new Netflix film starring Gary Oldman as Herman J. Mankiewicz.