The problem for freenet/gnunet/tor etc is that they achieve their anonymity by inefficiency (organiesed bunch of proxies).
Distributed dynamic content would be more efficient than distributed anonymous dynamic content.
The music and movie cartels could still go after compyright infringers, but they would have to go after the little bloke, which is a tactic they they have already tried and given up on.
The goal of science is to build better mousetraps. The goal of nature is to build better mice.