Re: Composers - I don't think the comparison is fair. A negative should be compared to the sheet music in my opinion, and a print, which is an interpretation of the negative, should be compared to a musical interpretation of the sheet music. We cannot listen to something that Beethoven conducted, obviously, but luckily there are many talented conductors that can. While we can never know exactly what Beethoven's preferences were, other than historical records, at least we have the sheet music.
With a photographic print, we're still in an age where prints made when the artists were still alive can be viewed, as a testament to their preference and decisions made while they printed them, and that is of tremendous value in my opinion. For example, I forget the name of that New York photographer whose negatives they found recently, documenting the city over decades. Finding those negatives holds tremendous value, but I think if they had found prints also, that would have been even more valuable. That would have been equal to knowing how Beethoven would prefer that his musical scores were performed.
I agree that future technologies may take us places we haven't even imagined yet. I have no idea whether I will like it or not. Only time will tell. Opinions change and vary with experience, that's for sure. I'm only 40 years old, and have been through many changes already, and I'm curious to find what the future holds.