Though at times frustrating, Sam Mendes’ approach to 1917 gives viewers an idea of what life must have been like on the World War I front lines. The Great War rarely gets the cinematic treatment, so this intimate glimpse into harrowing conditions that soldiers faced is notable. The dedication to realism also drove the director’s decision to cast two relatively unknown actors as the leads. He told Variety that if he’d had A-list actors play the main characters, viewers would automatically assume they will survive, and become less engaged in the film’s outcome.
Article source: https://www.cinemablend.com/news/2486292/sam-mendes-explains-why-1917-needed-to-feel-like-one-long-shot