Untestable theories and love at first play
I have a suspicion that songs with simple chord progressions began with a riff or progression and that songs that started with the melody end up having a million chords or chord progressions that don't seem to follow simple patterns.
Simon and Garfunkel's - America
(I am not convinced that this is quite the progression, but I think it's pretty close)
Queen's - Killer Queen
The Magnetic Field's - I Don't Believe You
Mind you, I have never tried to write a song on the piano. It's possible that piano composition lends itself to writing songs with more than four chords.
But I do know that Stephin Merritt is dreamy. With the line "So you quote love unquote me" I was hooked. Add to that fumbling my way through the song - call me a goner.