I don't think it's dead, but it is in a lull... but it's not the first time that rock has not been in fashion. True it is not doing so well in charts, but that will only last so long. At some point the dominance of factory music and the covers of a small subset of songs will wain.
Rock has always more freely embraced indie, and indie music frequently doesn't show in charts... why? Because the location that chart music is drawn from is very limited. Download sales are now more influential, but those download sales are drawn from a small subset of music sites, and those sites frequently are more pop oriented with an almost zero representation of rock and indie on those sites.
In the same way that the obessession with celebrity culture in it's current form will pass, so will the pop music fads. As mentioned before it's a cyclic thing. The difference this tmie is that the effects of piracy has driven certain genres to the brink, to the extent that it now shows in even larger followed genres such as rock. A few years ago jazz and folk felt it. Okay they all feel it, but pop is still currently supported by the main media and that is propping it up especially with shows like "XFactor" and "x's Got Talent"... in fact those sort of shows supply the main backing of pop music. If there was a rock equivalent no doubt rock would surviving piracy better than it currently is. Lets make no bones about it, piracy is still wrecking the main changes in the music. Rock is certainly the most obvious sysmptom of that problem.