I cannot believe that I am merely a product of living in the modern world.

I cannot listen to a melody without hearing the chord structure and understanding the possible harmony lines that could accompany it. I usually cannot sing in unison as my voice range is not capable of singing the melody line at most people's pitch so I sing a harmony.

Leaving aside the impact of the lyrics, a single line of melody is very rarely of sufficient interest in itself, the interplay of harmonies is what captures the ear in most cases.

To me this is intrinsic in music and throughout history a single line of melody is surely not what music is.