I wonder what he would make of _I Am The Walrus_, which uses every note-named major chord (A, B, C, D, E, F and G major).
Despite the complex chords, the bulk of the melody is that ultra-simple two-note semitone riff (IIRC Ian MacDonald’s book says it was inspired by hearing a police siren). When John Lennon said someday they’d write a one-note song I always figured this was what he meant -- that I Am The Walrus is a “two-note song”.