Combining Schenkerian-style graphs with rock-inspired salience conditions can provide the solution to this problem. This paper proposes a linear analysis of The Beatles' "Lucy in the Sky with Diamonds" based on the combination of modified Schenker graphs and newly created Rock and Pop Salience Conditions (RPSCs) influenced by Lerdahl's Tonal Pitch Space. As in Schenkerian analysis, the musical events on the graphs with structural weight will be given open or filled note-heads and/or stems of varying length to show their importance in terms of salience in the absence of tonal function. Thus, a rock or pop song in multiple keys along with all of its idiosyncratic voice-leading issues may be represented linearly and hierarchically using a Schenkerian-style graph influenced by these RPSCs.
Thus, answering Bernard's charge, while it is difficult to come up with a general theory of rock, combining multiple existing theories may, in fact, provide a more meaningful solution in the meantime. Until one unifying theory of rock is found, then a combination of old and new theories must be employed to gain greater understanding of an ever-growing repertoire of modern music.
Reference:
Bernard, Jonathan W. "Review of Allan F. Moore's The Beatles: Sgt. Pepper's Lonely Hearts Club Band and Walter Everett's The Beatles as Musicians: 'Revolver' through the 'Anthology.' Music Theory Spectrum 25/2 (Fall 2003): 375-82.