While I think some of the evidence in support of torrenting is more than a little suspicious, I do question whether or not heavily fighting it can provide value.
That is, I don't know how many folks that torrent stuff do buy stuff. Anecdotally, I actually just don't know that many folks that torrent. Of the few I suspect do torrent, they wouldn't be buying anything anyway. At worst, they would have been fine with crappy taped copies from the radio. Or music videos on VHS. (Heck, as a kid I probably watched more VHS stuff than anything else, and we bought videos.)
So, my hypothesis is that the amount of money and effort that is extracted from and goes into fighting music torrenting eclipses any supposed money that was lost in the crime.
I'm definitely game for any links. Or ideas on how to explore this hypothesis.