Singin' in the Rain to Vertigo to Seven Samurai. The last decade of the classical Hollywood studio system at full operation.
The 1950s is the last decade of the classical Hollywood studio system. The seven major studios — Paramount, MGM, Warner Bros., 20th Century Fox, RKO, Universal, Columbia — were operating at the height of their internal-resource model: contract players, in-house writers, owned cinemas, vertically integrated production-distribution-exhibition. The 1948 Paramount Decree (which forced the studios to divest their theatre chains) had begun the system's slow collapse, but the 1950s is when it was still functioning.
What's notable about the decade is the range of high-quality work produced. Musicals (Singin' in the Rain, An American in Paris). Noir (Sunset Boulevard, Touch of Evil). Westerns (The Searchers, High Noon). Method-driven dramas (On the Waterfront). Hitchcock's mature period (Rear Window, Vertigo, North by Northwest). Internationally, this is also the decade of Kurosawa's foundational work, Ozu's mature period, Bergman's first major films.
The 1950s gets dismissed sometimes as the decade of conservatism — McCarthyism, social conformity, the suburban consumer fantasy — that produced relatively safe American cinema. The dismissal is incomplete. The decade also produced significant work in the disreputable genres (noir, science fiction, Western) that the conservative consensus dismissed as B-pictures. Many of those B-pictures, in retrospect, are among the most-respected American films of the period.
Internationally, the 1950s is one of the most-productive decades in cinema history. The Japanese New Wave was emerging. Italian neorealism had matured. Bergman was in his first major period. Indian cinema (Satyajit Ray's Pather Panchali, 1955) was finding its international voice. The decade rewards looking beyond Hollywood.