Music fans will often give two points for when the music industry became like this. The first is the rise of MTV and music videos in The Eighties, which produced artists like Michael Jackson and Madonna. An artist's image was always important (just ask Elvis Presley, The Beatles, David Bowie...), but the visual medium of music video meant that they and others were defined primarily by their images, rather than just their music. This has been called the start of the music industry's equivalent of the Blockbuster Age of Hollywood, one less about the music and more about the profits -- much more than usual, anyway. Of course Your Mileage May Vary, since the music of the era, including the two artists named, is often well-regarded in spite or even because of the focus on image.