When someone asks Harlan Ellison where he gets his ideas, he tells them he uses a service in Schenectady. He gives them $30/month and they send him a six pack of ideas every week.
Ideas are easy and cheap. So cheap that they are functionally free. Turning those ideas into something concrete is neither cheap nor easy. Creating a song, a story, a painting, a sculpture, or an app takes a tremendous amount of effort. When a songwriter has an idea, it doesn't just magically appear on the page. The songwriter has to work to put it there. When I get an idea for an app, it takes a lot of effort to turn it into something that can be released.
The value in an mp3 is not in the bits themselves. Bits are cheap. The value is in the novel arrangement of those bits into something that is desired. When you copy an MP3 without paying for it (where applicable), you are conceptually walking into an art gallery and walking off with a lithograph without paying for it. It doesn't matter how many lithographs are available, you still walked off without paying for it against the wishes of the creator of that lithograph (after all, there would be no lithograph to steal if someone didn't come up with the source material.)
An executed idea in the form of an MP3 may be valuable, but it is not worth an unlimited amount of money.
When IP is sold in the same way as physical goods, it can be sold forever - this is problematic because notions of theft depend on the victim being unable to use the item that has been stolen.
The way you are refering to theft is far closer to what a legal professional might refer to as potential lost revenue. Even so, this is still questionable as many of these MP3 thieves wouldn't have paid in any case.
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"When you copy an MP3 without paying for it (where applicable), you are conceptually walking into an art gallery and walking off with a lithograph without paying for it. It doesn't matter how many lithographs are available, you still walked off without paying for it against the wishes of the creator of that lithograph (after all, there would be no lithograph to steal if someone didn't come up with the source material.)"
No. No. No.
How on earth can this be a fair comparison? A lithograth is printed on paper or vellum. Stealing the lithograph would be similar to stealing a CD.
If you want an analogy that is fair .. perhaps the visitor to the art gallery walked out with a photograph on their camera or a JPEG file. Neither of which should constitute a crime in my opinion.
Ideas are easy and cheap. So cheap that they are functionally free. Turning those ideas into something concrete is neither cheap nor easy. Creating a song, a story, a painting, a sculpture, or an app takes a tremendous amount of effort. When a songwriter has an idea, it doesn't just magically appear on the page. The songwriter has to work to put it there. When I get an idea for an app, it takes a lot of effort to turn it into something that can be released.
The value in an mp3 is not in the bits themselves. Bits are cheap. The value is in the novel arrangement of those bits into something that is desired. When you copy an MP3 without paying for it (where applicable), you are conceptually walking into an art gallery and walking off with a lithograph without paying for it. It doesn't matter how many lithographs are available, you still walked off without paying for it against the wishes of the creator of that lithograph (after all, there would be no lithograph to steal if someone didn't come up with the source material.)