Music, as an entertainment BUSINESS, has always had a visual connection to go along with the sonic end. The age of video took the emphasis off of the sound and made the image (or imagery) supreme-making the need for "musical ability" less important.
Image isn't new. Personally, I feel that Elvis sold as many records by shaking his hips as he ever did with his voice. Just my opinion. The problem is that occasionally, the visual end peaks out-meaning that the actual music is garbage, but "hey, look at my cool dance moves and sparkly outfit!"
Don't get me wrong. I think that the visual side is just as important. I also think that there's an art to it. For myself, however, I need to have it all (I'm such a pig!

) You can have the best video in the world, but if your song is drivel, you won't be getting any of MY money.