I have a different viewpoint. They only "copied" a chord progression. In western civilization, there are only so many "pleasing" note sequences. If you paid me to analyze every popular contemporary song, I'm sure I can find its roots in something older. In fact, the classic songs of the 60s and 70s are themselves based on songs from the 50s or older.
How come Lexus (Toyota) can copy a Mercedes, Samsung can copy an iPhone, Seiko can copy a Rolex, but in 2016, someone can't write a song which contains a 4 note sequence that was used in a song 40 years ago?