As I was driving to San Antonio this week I listened to "YYZ" thinking about your analysis. It was then that I realized the song is in Sonata form. Now, this is probably not intentional as most of the conventions of Sonata form are not followed (repeat of the 1st section, repetition in a key a fith away), but the basic approach of exosition, development, and recapitulation are there. I think more probably that our current musical masters have struck a method that musicians long ago uncovered. . . whatever that means