This song is really rooted on the tonic note. First verse eight bars, second verse is six interrupted by an extension. I guess you could call it a bridge. The melody starts on the third there, but quickly deflates down to that tonic.
More verses afterward, but now he's singing it an octave higher. And so it builds, slightly more involved melodies, running through that extension once again. Eight lines ending with the beautiful symmetry of those six-syllable lines that come at the end and then...POW!
The chorus! There, at 2:14, no longer anchored by the root. They've earned that higher plateau on the third scale degree now. Not eight bars and they're done; there's more to say. 16 bars, 44 seconds, and that beautiful, surprising internal rhyme at the end.
Repeat because they've earned that, too.