Song structure is not simply linear. It has different dimensions
(songwriting - topline and harmony, and production - sonic density and
energy).
It also works on different structural levels.
Internally, sections are usually shaped by the melody. The large scale form is mostly expressed through the sound production. Section to section progression relies equally on both.
Of course, not every song had to work like this but it's generally better to think of the various dimensions of a song rather than to think of it as a straight line. Songs that aren't developed on different levels usually sound too 'flat' unless they have something else going on that's amazing.
It also works on different structural levels.
Internally, sections are usually shaped by the melody. The large scale form is mostly expressed through the sound production. Section to section progression relies equally on both.
Of course, not every song had to work like this but it's generally better to think of the various dimensions of a song rather than to think of it as a straight line. Songs that aren't developed on different levels usually sound too 'flat' unless they have something else going on that's amazing.