'Instead of doing a really elaborate video, you buy them a support slot on a credible rock band's tour.'
This is called "the rub" in other industries - funny stuff. Through all the brand-building, style-creating, and media practising; a rock band can convince you that they are representing "what's real" and "honesty". I don't fault Keane - or any other band for that matter - they're good businessmen. And their music is pretty good. The industrial machine that is the music industry tells us what we want! And that what we want is authentic!
Oh, how I hope the continued advances in technology revamps the whole thing. Although it's going to result in a recommendation system that could be manipulated (ie "what i'm listening to now" on blogs; recommendations/reviews on gamespot/amazon being applied to music; etc)