I'll say a thing, among others I could have told :

Being in our minds, art is fragile. So it has to be established on various supports, such a canvas.

But a canvas is fragile. So it has to be established on or with other supports, or with other functions : financial value, prestige, museums, decoration etc...

Perhaps that's something unevitable.

And that's why your post aim at separating what's art and what's only its various "supports".