http://news.bbc.co.uk/1/hi/magazine/3117505.stm
BBC writer has some reasons very different from file sharing for dips in RIAA revenues. I think they are reasonable.
http://negativland.com/albini.html
Explanation for how the music industry works from someone who has been involved in it for decades (Albini produced Nirvana FYI)
My $0.02: I look at mp3s as being the modern equivalent to radio. The RIAA does too, to a point. They think that they are entitled to revenues just the same as if the music was being broadcast on airwaves. The difference? A radio station sells advertising and makes money by having music playing. MP3s do not. I just find it ridiculous that I am able to take a cassette tape that I own and legally convert it to crappy quality mp3 by running it to line in on my PC, but if I download 256kb mp3s from the web of the same exact songs that I have broken the law.