He means that the "backyard-barbecue and three-martini" mother lode of American realism mined by an earlier generation of writers--writers from Updike country--simpy fails to connect with him, either as writer or reader.
Rather, Wallace is a descendant of that subversive, anarchic branch of American literature ("Nabokov's children," he calls them) that began veering off the main stem in the 1960s: novelists such as Thomas Pynchon (Gravity's Rainbow), John Barth (The Sot-Weed Factor), Robert Coover (The Public Burning), William Gaddis (J R, The Recognitions), and--Wallace's favorite--Don DeLillo (White Noise, Libra).