Sure Elvis went Hollywood and then Vegas which removed some of the hillbilly from rock, but you can't really say it died unless you make some sort of artificial barrier between country and folk music. Folk music covers a wide range of styles and most white, American rockers started out as folk singers in the late 50s thru 60s. Even the future psychedelic bands in San Francisco (The Dead, Airplane, Quicksilver, etc.) had strong folk roots. And let's not forget the whole Bakersfield Sound which contributed that country swinging tonk thing. If you listen to the critics rock 'n' roll has more sub-genres that western classical music (1600-1905). It's not true. If it has a back beat and is played with a certain attitude, then it's probably rock.