I DO NOT believe that any of us has the right to FORCE an artists to adopt a business model that they don't wish to adopt. This is where you cross the line from "perfectly moral business proposal" to "immoral use of force."
Ah but markets force people to change their business models all the time. They call them 'market forces' for a reason. Markets change as a result of technological changes. The market for recorded music was created by technological change (vinyl records) and is being destroyed by technological change (digital music). Market forces are not immoral, but they will force people in the market to change their business models, even against their wishes.
OK, so we're there, basically. You're agreeing that there is nothing inherently immoral in sharing music (or any content), the immorality is that someone, somewhere, way back up the chain broke an agreement that they had with a licensee of the original artist, and that makes any sharing of that content immoral.
There's one small but obvious flaw with this...the music doesn't come with an attached licence. I don't know if a track I'm downloading is immoral or not. I don't know if the artist whose music I'm listening to has agreed to this use of their content or not, so I don't know whether downloading the track is a moral or immoral action. Nor, as a consumer, can I be expected to know this. I could make the blanket assumption that copying any music is immoral, but that's not a valid assumption when there are musicians who are experimenting with new business models and who want me to share their music (as you've pointed out, this is probably the future of music). I could purchase all my music from music stores, but again that would rule out new business models that involve sharing which I'd like to encourage. I file my music by genre not by licence conditions.
Incidentally this isn't a new problem in the music industry. There have been cases where unscrupulous record distributors have made compilation albums of music without the agreement of the original artists. The purchasers of those albums are obviously acting in good faith, and yet are recipients of illegal, immoral music that they should immediately return to the store for a refund if they knew. Except, of course, that they don't know and can't be expected to know.
Obviously if I purchased some music and there's an explicit agreement that I have signed/clicked on with that purchase that says 'don't copy this' then I'm breaking a rule by copying it, and I'd agree probably breaking a moral code. But there's a wide range of activity here... am I allowed to format-shift my music, is that breaking the 'no copying' rule? I'm obviously allowed to lend my CD's to friends, so can I format-shift my CD's and lend the subsequent mp3's to friends? If I lend my CD to a friend and they then copy it, am I breaking the agreement I made with the artist, or is my friend who didn't make any agreement?
To take a real-life example again... I move in with a girl. We merge music collections like we merge everything else in our lives. We buy music together and format-shift the resulting tracks to our mp3 players. Then we split up because sometimes these things just don't work out, and amongst the endless hassle of splitting apart the joint life we created, we each take a copy of the entire mp3 collection that we bought. I'd argue that attempting to make us go through a process of identifying each track's original licence conditions to determine whether that music track can be shared or if we need to have an argument about who gets to keep it is pointless, futile, and if your business depends on that happening then your business is broken. And no, I don't think this is the moral equivalent of firebombing a Mcdonald's, and any attempt by the music industry to portray the two actions as morally equivalent is just plain wrong.