This is much like the war on drugs. It's not going to work.
In my opinion this is no different than me recording a song off the radio, burning it on a CD, letting my friend make a copy, who lets his friend make a copy and so on. Would they sue the radio station?
This won't work with torrents. They may be able to shut down a few torrent search engines, but as soon as one gets expunged, three more will appear. And suing individuals for sharing songs? That's a quick route for fans to boycott the recording industry.
Offering high-quality MP3 downloads for a reasonable price is how it will have to be done. There will always be piracy. As an artist, I might be upset that all my songs are being pirated, but I would be equally upset at how much of that money I generate for the record companies is being spent on suing file sharing sites. It's futile.
You can't sue your way back into the 20th century!