Isn't that the role that Anonymous, LulzSec and (in a way) Occupy have been filling the last few years? Tilting at very big windmills and being socially, culturally and politically disruptive - sometimes constructively and sometimes not - seems very Punk Rock to me while actually achieving more and taking bigger personal risks than any Punk band I can think. Just because rock n roll has failed to be a rallying point it doesn't mean no one is rallying around something similar. At the Million Mask March gathering in Trafalgar Square all I could hear was Reggae and Dubstep which might speak volumes for how rock (punk or otherwise) is seen in terms of being a rebel music these days.