This article (Andres Guadamuz, TechnoLlama) is pretty detailed and has pretty good analysis on why the RIAA and MPAA's repeated cries of industry-ruining piracy are wrong.
Let me simply say that as more legal digital sales occur, piracy drops. Also, there is a wave of renewed interest in actually going to movie theaters and music concerts (as opposed to buying albums or film DVDs). However, neither the RIAA nor the MPAA wants anyone to believe this.
