Rod McKuen is not a real poet. He is a popularizer of light verse and his song lyrics are
not poetry. Neither are Bob Dylan's or John Lennon's. What we see today is an ignorance about what constitutes poetry. Artsy-fartsy songs by many of today's young songwriters are not poetry.

Poetry is not lyrics. It has to be evaluated on the printed page and sometimes read aloud.
When you put music to it, then it becomes a song. Not all poetry will work as a song.

To call a songwriter a poet is to call an oil painter a decal designer.

Songwriting is a special talent and skill and lyric writing only works when there's a melody for it.