Music is an art and it evolves with time. Every period and every work is unique. Some music will be liked universally by majority during different eras. And some will not be liked in an another era. I think there are two main types of musicians. One who compose music from the artistic point of view and they only care about their creativity and satisfying their soul. Another category churns out music keeping the commercial market in mind. They too are creative but might make some compromises and add things which they would not do otherwise. Then there are different shades among these two groups.

Technology has been very helpful in the evolution of music.

I agree that encountering music in the past would have been a special and unusual event. Probably even the highlight of the day/week/etc.

I think the modern world has also changed our expectations of music - we can't pin this entirely on technology, but it probably has to do more with how modern consciousness has evolved with the technology which allows us to communicate, record and interact much more easily. May I also say technology which allows us to "edit"? ;)

I've noticed that many musicians today direct their energies towards a special "event", such as a concert or a recording session.  It'd be nice to see more jam sessions or families who play music at home for enjoyment. Of course this does happen, but most of the time I see rehearsal for something specific.

I guess I'm saying that in some ways, we expect a certain (unrealistic) "standard" from musicians without fully understanding the practice and process that goes into the finished product that we hear. Unless we're watching a live gig or a rehearsal, we're usually "protected" from the muckups, bum notes and even shambolic "train wrecks". Instead, we expect quality music in a convenient way - sometimes even for free.

On another note (see what I did there?), I was recently thinking about how the recording of music has evolved through basic musical notation, to sheet music, to vinyl records, cassette tapes, CDs, and then to computer files... so far. It's almost as if technology has made music "immaterial" once again. :)

Well, I was litstening to Britten's War Requiem at the moment I saw this discussion, and I think it is mindblowingly beautiful. But if not for the technology, I wouldn't have the recording.

There was a modern classical composer (I Don't remember name at the moment but I will find It) He composed a lot of pieces but no one ever recorder, he believed that music can not exist in the records  but only in the same time it is played, So hear it by technologycal tools it's like hear phantom sounds, maby photogray is a good example, we can see a photo and fell a lot of emotions but we are not there it's just a perceptive experience. Personally I find this concept very tenderhearted and interesting. (Anyway I confess that I couldn't live a world without my MP3!!! :p) 

Yes Peachey, Immaterial is a wonderful word to describe it, It's a continuous, fascinating and evanescent evolution