There is a difference between copyright of the song lyrics and music, and the copyright of the production (the sound recording). The producing company (i.e. record label) generally has the copyright on the production, and the artist might retain the rights to the lyrics/music, or sell them as part of the contract with the label. The lyrics/music copyright is sometimes sold to yet a different company.

If the artist chooses to sell their copyright, that's fine with me. The savvy ones tend to get a good price, the naive tend to get screwed (and become "slaves") but that's a different issue.

Also, the issue of whether the artist is hurt by file sharing is not the issue. There is certainly too little data to do other than speculate on that issue anyway. The point I'm trying to make is that the copyright holder has the legal right to control reproduction of the product. To allow it to be otherwise impinges on the ability of creative minds to reap the benefits they have earned.