A tangential post-script to the words below. I am often wary of giving the impression that I think that Hollywood was better (at everything) in the past, and is now nothing more than an imitative shadow-machine of its former self. I think that commercial cinema, in Hollywood or elsewhere, exists as a combination of truths and lies that come encapsulated along the terms of a "contract" (probably could use a better word here, but it would need unpacking: later maybe) between the minority who produce and the populace who view these products. The terms of this Hollywood/populace negotiation are themselves constantly being re-negotiated. In juxtaposition to whatever lies Hollywood told in the past, our present perspective gives us historical views of what the films did not necessarily lie about, but which are being covered over today. I think Hollywood had a lot more honesty about certain aspects of class and poverty until roughly 20-30 years ago; these aspects were able to come through with relative honesty because illusions about these things were not included to the same extent or in the same way in the ideological projects of classical and 60s-70s Hollywood. It is a matter of looking at our cinematic past—which is still living today, as these films are still "products" for the populace—obliquely, and understanding through the vantage points of structural shifts in the system how films (texts/products) come to say things that they were never initially intended to say; how they say things that may not have been noticed before.
This is not a matter of finding subversive or countercultural (in a broad sense) meanings built into films, which is a different issue. It's a matter of finding the things that a system did not take the care to lie about or stylize—at least not in the same ways as they finessed other things which we now clearly, in allegedly enlightened manner, see for ourselves. The negotiation of businesspeople, creators, and technicians to audiences crystallizes into specific film texts. Studying the changes in producers/audiences in tandem with the study of textual/generic/authorial productions gives us a better understanding of the long history of a commercial cinema, the history of the choices offered to every type of player at different points in the game.