Well I'm not really convinced that it's only a matter of perspective. Of course to a certain degree, we could say that everything is avant-garde, only relating to this or this dude's musical tastes and knowledge. But if you're to seriously try to understand what is avant-garde in itself, not as a word among others nor as a fashion or a trend, but as a real, palpable artistic phenomenon, I would say that you have to dive into basically all existing kinds of music. ALL of them. Then it is easier to judge what is and what is not "forward-looking", or what has or hasn't been made before. If someone only listens to a one-dimensional musical universe, be it Britney Spears or Darkthrone-like BM or whatever, who cares about what is avant-garde for this person. It will of course be limited to his small perspective.
Let's have an image. You want to study physics at University. There's that one man who has never even studied it before, who never went into outer space, who never experiments with matter particles and vacuum, who isn't even into elementary degrees of mathematics. But his father occupies an important role at the University and wanted his son to teach physics, and there he is. Then there's that astronaut just coming back on Earth after a 10 years voyage on planet Mars, whose knowledge is not only rooted into past books but also into real and personal experiences and investigations. He has seen our planet as a grail of sand among all the other stars. He has felt inside him what is outer space, he lived it. Let's say he even had a LSD trip in his spaceship.
The first man comes to you and says: hey dude, let me teach you about the relations between mathematics, earthly physics and cosmic black energy. I'll tell you what's possible and what's not out there! Listen to me kid, I basically know everything and I'm paid for it! I can already state that it is scientifically impossible to have a LSD experience in a weightlessness state, so be careful when you hear that arrogant man who thinks he knows everything, and who says that I was only chosen to teach because my father is working here. He's a lyer!!
The second man comes and says: if you want to learn about space traveling, lsd weightlessness powers and cosmic physics in general, come to my class. Here we'll concentrate ourselves on experiences and facts, let's forget about my ego, I'm just a passage between outer space and my students.
What is gonna be your teacher choice? Mine is clear enough. But the question is: these two guys obviously have two distinct perspectives on the matter of cosmic sciences. You can say to yourself: well, both of them have a valuable teaching, because both of them offer a different perspective on the same object. The more perspectives you get on the same objet, the more you get to know what it is. Or you can think: of course I'll go and listen to the astronaut because his experience is far more expanded than this little colon-licking daddy's ignorant boy. Personally, I'll take the second option anytime, there's no question about that.
I think it's the same with avant-garde. Britney can tell every journalist that her last album was original and forward-thinking, but who cares if it's not compared to any European techno artist? It's like Nocturno Culto saying that the next Darkthrone album is gonna be "special" and like nothing he's done yet. Maybe it's different if you compare it to Transylvanian Hunger, but in the end it is nothing else than metal right?
Yeah sure, perspective is an important part of our lives. Everyone's perspective, in some way, can be interesting. But I also believe that the ones who are experiencing everything possibly experiencied in the realm of music, have a more valuable comprehension of music than anyone who is always limited himself to more restricted areas of sound.
I'm not saying, though, that it's easy to explain what avant-garde is, and I'm not the one who can handle such a question! But perspectives aren't going to give us an interesting answer, other than a psychological one. Saying that everything is a question of perspective is limiting every object of experience to who perceives it. As a biopsychologist, I may want to know about who perceives it because my quest is to understand perception in itself, but as a physician, I want to know about it, that's all!
I don't want to sound arrogant or anything but I just think that perspective is a very limited realm when you seriously want to understand and experience what is the very nature of an object. Mathematics aren't only mathematicians, just like music isn't only the sum of its listeners. Do I make some sense here or?