Understanding auteur theory
Filmycks DIRECTORS SUITE is a good way to 'follow the money'. The French Nouvelle Vague writers popularised the 'Auteur' theory in the 1950's, placing the Director at the helm of a film's artistic vision and, by and large, it's a theory that holds up today. Any major director that has amassed a significant body of work usually leaves their fingerprints behind, like following a great band or singer you'll find following a director will help negotiate the seemingly endless maze of 100 years of accumulated viewing options. Cinema is a collective art form, and any pulling together of the many disparate elements works best when that person has a singular artistic vision and can harness all of the contributing factors to fit that, hopefully unifying vision, to achieve the best result.
During the 1950's, the writers of film criticism at French magazine Cahiers du Cinéma, (including François Truffaut, Jean-Luc Godard and Claude Chabrol) founded by André Bazin in 1951, developed a methodology of examining film content based on what they identified as Mise-en-scène. It was a term used in theatre denoting visual themes or stage design, and they applied it to cinema to mean, 'everything that the camera sees'. The camera is the audience, it sees for the viewer, and so they asked, 'who determines everything that is laid out for the camera to document'? The answer they came up with was, the director, and this led to the now famous 'auteur' theory. My disclaimer in thinking about how this applies across the entire scope of cinema is to paraphrase Orwell, i.e. All directors are auteur, some are more auteur than others.
In the over 60 years since it's delineation it seems the landscape has shaped to fit the theory, in that most of today's major directors fit neatly the textbook definition of an auteur. This was not always the case, Hollywood and other producer's controlled most early cinema environments, and if anyone was an 'auteur' in that era it was probably the producer. Sam Goldfish (later Goldwyn), David O. Selznick and Irving Thalberg were notable examples of early producers who helmed projects with a coherent style. Some early 'auteurs' would be D. W. Griffith and Charlie Chaplin in America, and Murnau, Dreyer, Lang and Abel Gance in Europe. The studio system favoured the influence of producers during the 1930's, and only the strongest of personalities amongst the many directors who worked within that system makes applying the term 'auteur' to them either meaningful and appropriate.
The French writers singled out titans like Howard Hawks and John Ford from that era to be nominated as auteurist, but in truth, some of their output was still process line fodder. Even within this rubric some notable exceptions could be argued, like Robert Riskin as co-auteur of the Capra classics, given that the humanist sensibilities of those films that created the success stemmed from Riskin's leftist political slant, not Capra's right wing bias. Other workhorse directors like Michael Curtiz worked on the production line tirelessly and he would always turn out an efficient job of work, but when all the elements clicked, he could produce a timeless classic like 'Casablanca'. Another exception would have been Val Lewton at RKO, even though he hired great directors, it was his unmistakable fingerprints left on the dozen or so classic horror films his hermetic film unit put out under his auspices.
It seems obvious that many strong directors at the time looked for projects that suited them, aided by smart producers like Daryl F. Zanuck, who could marry the right talent to the right project. One was unlikely to hire George Cukor for an adventure film, or Raoul Walsh for a women's period costume drama. A few examples of this approach, directors who managed to practice a personal cinema within the confines of studio parameters and who caught the eye of the French writers were Nicholas Ray, Orson Welles, Elia Kazan and of course Alfred Hitchcock.
After WWII, the centralised power of the big studios started to diminish, and smaller production companies sprang up who leased product back to the majors. Many of these companies were set up by independent directors, looking for greater control over their output, or by ambitious actors, keen on having input into their career choices. It made sense for people interested in creating the optimum work of art to fight for control over the entire process, however messy and unwieldy that process may be, and after the critics at Cahiers du Cinéma formulated their arguments, most of them went on to become significant directors themselves. The success d'estime of the Nouvelle Vague directors meant that the auteur theory became holy writ within film criticism, and continues so to this day.
There are some exceptions to every rule, recently some singular writers would have claim to authorship, such as Charlie Kaufman, who's five films as a writer chime neatly with his first film as a director to produce a consistent tone and voice, even though the early films are directed by three very different directors. Of course there are pivotal artistic contributions from cinematographers, actors and writers et al, across every film, but it would appear for a film to fully succeed it must be controlled by a single artistic vision, and the person best positioned to make that happen is, and probably will remain, the director.