Carmine Appice, the main writer of the song and Stewart’s drummer envisioned it more as a take on of “Miss You”. It was to be heavier. Then they added those damned string or string synths to it. Like s DX7 to 80s cheese it instantly dated it. He said this on Stern I believe. Appice is definitely a master songwriter/arranger. They should have listened to him.
Well as the quote from Hitchings points out, Stewart wanted to do a parody of disco lounge lizards. How would that work making the song heavier and grittier? Don't get me wrong, the song was annoying even then let alone now but as a marketing move it was pure genius.