A few movies have a Unity to Disunity structure: The Conversation, Se7en, Chinatown, The Magnificent Ambersons (original ending), Kiss Me Deadly, The Long Goodbye, Homicide (and many other Mamet stories) Invasion of the Body Snatchers (original ending) e.g. I think the point is to undercut the faux unity of the protagonist without providing a solution other than accepting disillusionment.

Even if the protagonist fails to accept disillusionment, the audience does and gains a sense of (tragic) unity.