Simon Reynolds make a great point in The Wire's 2008 Rewind issue, already posted here [broken link] by a different writer as part of an excellent essay regarding the difficulty in holding exclusive convictions in the face of so many different musical ideas:
As young musicians develop in a climate where the musical past is accessible and available to an inundating degree, you encounter artists whose work is a constellation of exquisite taste, a latticework of reference points and sources that span the decades and the oceans but never quite manages to invent a reason for itself to exist.
Perhaps the showing of reference points and taste is the reason for the music to exist.
What I find interesting about this state of affairs is how much it implicates genres that have a history of rebelling against this sort of thing. It used to be that it was solely pop, solely "the mainstream", solely, ultimately, Capital, that had this sort of blind yet voracious desire for anything and everything that could keep itself going. What defined any genre that stood against this was distinction, was specificity, was a tangible agency. Pop was seen as product, something that didn't need a reason to exist, it just was.
A quick very general theory of recent American rock history:
80s: Pop is crap, meaningless, lacking rationale. The antidote is to make music specific and meaningful, underground.
90s: Pop is meaningful. The popularity of Alternative pushes the heartfelt convictions of young men and women out to the forefront of consciousness. Three reactions: 1) not seeing this meaning as the corporate product it became and buying into Alternative and its aesthetics, in which case you may still listen to modern rock radio to this day, 2) seeing meaning as corporate and taking meaning in music in direction that is more quirky, more individualistic, less universal or communal or, 3) seeing meaning as corporate and using irony as a way to interrogate questions of meaning, as a way out.
00s: Pop is meaningless again but refreshingly so. Indie reactions against the popularity of Alternative are unsatisfying, Justin Timberlake is not. Now all music is equally valid. Irony becomes a self-delusional tactic. You do like Britney, you do like disco, you do like Christopher Cross, and the fun of music is showing these likes off, but you don't believe. Irony is no longer a tactic to interrogate values, it simply shows the lack of them.