It is a long, winding essay, with continual payoffs. Central to his argument (helpfully noted in a section subtitled, "I do have a thesis") is the recognition of the self-consciousness, ironic layering of television, such that television had already beat postmodern novelists to the punch. The general cultural ethos, then, is shaped by "irony, poker-faced silence, and fear of ridicule."
In lieu of a long commentary, let me just give you a taste of Wallace's claims and criticism, which I think are only more true today. For example, consider this little meditation on fear of ridicule:
"And to the extent that it [TV] can train viewers to laugh at characters' unending put-downs of one another, to view ridicule as both the mode of social intercourse and the ultimate art-form, television can reinforce its own queer ontology of appearance: the most frightening prospect, for the well-conditioned viewer, becomes leaving oneself open to others' ridicule by betraying passé expressions of value, emotion, or vulnerability. Other people become judges; the crime is naiveté. The well-trained viewer becomes even more allergic to people. Lonelier" (p. 63).Thus the dispassionate aloofness of a generation of passive viewers:
"In fact, the numb blank bored demeanor--what one friend calls the 'girl-who's-dancing-with-you-but-would-obviously-rather-be-dancing-with-somebody-else' expression--that has become my generation's version of cool is all about TV. [...] Indifference is actually just the '90's version of frugality for U.S. young people: wooed several gorgeous hours a day for nothing but our attention, we regard that attention as our chief commodity, our social capital, and we are loath to fritter it" (p. 64).This is then followed by a similar phenomenology of irony, of which a slice here:
"The assumptions behind early postmodern irony...were still frankly idealistic: it was assumed that etiology and diagnosis pointed toward cure, that a revelation of imprisonment led to freedom. [Rortyan irony?] So then how have irony, irreverence, and rebellion come to be not liberating but enfeebling in the culture today's avant-garde tries to write about? One clue's to be found in the fact that irony is still around, bigger than ever after 30 long years as the dominant mode of hip expression. It's not a rhetorical mode that wears well. As Hyde (whom I pretty obviously like) puts it, 'Irony has only emergency use. Carried over time, it is the voice of the trapped who have come to enjoy their cage.' This is because irony, entertaining as it is, serves an almost exclusively negative function" (pp. 66-67).
"Make no mistake," he concludes: "Irony tyrannizes us."