As much as I am a defender of P2P programs like Napster, Gnutella and the like -
There WAS a decided drop in the sales of the mainstream acts. Not much of one. And also not something the artists would ever feel beyond the record labels inflating it and passing it along.
That being true, for every 'big name' act that a major label lost a tenth of a decimal place on, there were other smaller independent groups that gained valuable exposure that are now shut out of the new 'pay to trade' models that the record labels have created as the acceptable (for them) model.
It'll all work out in the end. Every time that a service goes down, a host of new non-centralized services spring up. And every time that the major labels figure out a new encryption, someone with too much time and equipment will break it and disseminate that knowledge to the cogniscenti.
The unfortunate side is that the average buyer loses all the way around. We've lost the ability to preview before buying, research and listen to new acts that would otherwise not likely be heard (I've a collection of Great Big Sea, Young Dubliners, Tempest and a few others that bear that out. Wouldn't have even known about them beyond occasional mentions here, wouldn't have bought them had I not heard them online). There's an ongoing fight to strip consumers of their right to copy for their own use recordings that they purchase.
Sad.
M