Is the medium really the message?

I'll come right out and say that I don't completely buy McLuhan's assertion. He seems obsessed with industrialization and links the specificity of transportation to art. I don't disagree that the railway "accelerated and enlarged the scale of previous human functions," but an artistic medium is different from an industrial process. In arguing that the medium is the message, I feel that McLuhan is overly homogenizing entire styles of art. If the content is just the distracting juicy piece of meat that he asserts it is, why bother making new art? Such an emphasis on form over content devalues the artist and overvalues the engineer or inventor who creates new forms of artistic expression. Different artists utilize a given medium in very different ways, even within similar schools of thought (e.g.: the French New Wave).
McLuhan argues that "the effect of the movie form is not related to its program content." However, I don't quite understand what he means by "movie form." Does he mean to assert that any series of images projected in front of a lightbulb on a moving strip of images is essentially the same? One only needs to juxtapose the work of Bela Tarr and Sergei Eisenstein to realize the absurdity of such an assertion. Film can explore time and space, but also can sacrifice either notion for the other or lose track of both. Stan Brakhage's more abstract pieces (those that involve directly painting on strips of film) illustrate this point. Below I've included a clip from Bela Tarr's Werckmeister Harmonies and Eisenstein's October, just to illustrate two very different filmic experiences. Even more different might have been a clip from a Tarkovsky film, but I just really love the opening scene to Werckmeister Harmonies.