Notice how often fans ask of singers, what did you mean by that? and they expect an ethereal meaning to the lyric.
Once somebody asked Paul Simon about the song with Joe Dimaggio in it. Did you know him? How did he came into the song? Is there a baseball metaphor?
Paul Simon just deadpanned: Because it rhymes.
I say lots of products use "S," not just the iPhone, because marketing research found "S" to bring positive connotation to people, like Rappers often call themselves "Z" something to sound cool. Doesn't mean anything. People seems to search for comfort in meanings. Sometimes... a cigar is just a cigar.