Provocative thought of the day

Popular music certainly affects culture - it's hard to look at Elvis, The Beatles and indulgent hair metal and think otherwise. But it seems to me that music's influence on culture tends to be a one-way ratchet - toward anti-authoritarianism and anti-status quo. Lots of music movements have at their base a negative philosophy - punk and hip-hop cut their teeth on negativity, with the overtly positive artists ending up in Gap ads.
Not that I think skepticism and speaking truth to power are in any way undesirable, and I have always been drawn to music that features just this sort of critique of society, but I just wonder if it's possible to harness music to something culturally (not simply artistically) constructive? When you look at optimistic political campaigns, the songs they choose are invariably feeble. I expect to get slammed by HMZ expressing this bourgeois perspective, and I welcome it, as long as it's hitched to some comment on the role of music.
Maybe popular music is supposed to be Shiva, destroyer of the old and staid. But is that necessarily its only role?