This Best Picture win makes sense in the context of the time of its release: TV was becoming a real threat to cinema and audiences felt more attracted to stay at home (sounds familiar?), as consequence studios started to produce big, bombastic spectacles in order to bring people to the theaters, which explains the rise of subgenres such as the sword and sandals movies, or the grandiloquent epics that would come out in later years. And this worked in a way, because as you mention this movie was a massive box office success and it won the Golden Globe, and also benefited from the competition: High noon was successful but also very controversial due to being perceived as a critique of McCarthyism and the blacklists in Hollywood and Quiet man had John Ford already having a BP winner. So in hindsight it's a win that doesn't look surprising even it has aged horribly.