Reviews thus far have not mentioned Carl Jung, the psychoanalyst, or how Cosmopolis can be interpreted as a dream using Jungian symbology. Cronenberg's previous movie was about Freud and Jung, so it is no artificial stretch to assume that he would apply Jung to a story, or that De Lillo had also done the same.
In Jungian dream analysis, the limousine can be taken as a metaphor of one's self, one's course in life. Each visitor to the limousine ought to be considered an aspect of the occupant's personality, each separate and distinct. There is the intellectual who has been hired to "do theory,"the young one who has been hired to find patterns, the nervous security expert who has tested for system vulnerabilities, the visiting prostitute (profane) who is asked to help obtain "the chapel" (sacred). Each character represents an aspect of a single self. Throughout the journey to get a "haircut," (which is a Wall Street term for taking a loss), the outside security chief relays messages from "The Complex," which might be interpreted as the unified self.
I think this is clearly what Cronenberg intended. The fuller meaning of the movie resides in how the dream reflects the actual world, how it fits with the shared reality in which we all participate. How does this simple journey to get across the city reflect the pleasures and perils of existence? Can we really know the world, or can we only know ourselves? How is the main character a representation of the whole world, which has a kind of self, too? Does the ending of the movie reflect an outcome that is metaphorically plausible as an integration of macroeconomic, political, human forces shaping history?
Cosmopolis is an intellectual work, carefully crafted, and not at all pretentious, as some have said.