This premise that the Hot 100 is still any indication of what people are listening to is utterly ridiculous.
"Mainstream" music hasn't actually been mainstream for over a decade.
What sells the most and/or gets the most airplay (in various formats) is, by definition, the "mainstream."
Does that mean that rock is, literally, dead?
No. It still has an audience.
However, that audience is aging and shrinking.
Every generation has "it's" own pop (i.e., mainstream) music. Eventually, that generation stops buying records. At that point, whatever genre was pop recedes and becomes more of a niche sound.
The baby boom was such a large generation (encompassing, in some respects more than one generation), however, that it artificially extended the life of rock as the dominant format.
But now, the youngest baby boomers are in their fifties. They don't buy music-in any format-as much as they used to.
Meanwhile the generation that traditionally buys a lot of music--the teenagers and young adults--have different tastes: dance, hip hop, that horrible stuff that people call "country" these days. They're the dominant form of pop music now.
Sure some rock records get sold, just like some blues and folk music get sold. And occasionally, just like those genres, a particular rock record will sometimes break through. However, those occasional breakthroughs don't mean rock is back on tap any more than, for example, the "O Brother Where Art Thou" soundtrack sales somehow meant that folk was now the longterm chart king.
