The Good Old Days
A speedy observation: As the above frame (from This Property is Condemned, 1966) indicates, Classical Hollywood starts to take on a historicity and the patina of nostalgia as the studio system fades. One can read the significance on a number of levels. There's Coppola's script as new movie-literate writer-artist whose sensibility would come to distinguish the Hollywood Renaissance. There's the shift in cultural hierarchy, an earlier phase of which I'd discussed in my prestige film article. There's perhaps an ideological nostalgia going; I think that reading is particularly convincing in the case of the 1970s retro-classicism.
Now, of course, the 1970s is as likely to serve the function that the 1930s and 40s did for the 1960s and 70s.