Do the current canons of art history fulfill all that can be said?
No, they do not. Modern and Contemporary art movements in their unaware pursuit for more creative freedom lost the true purpose of life and art and their essential virtues.
Art has now lost its true nature so utterly that every... purposeless, meaningless, un-composed, ugly, expression arising from unaware, mad, out rush of creative energies is being viewed as art. Contemporary art has no definition to follow and no good canons to evolve it in the right direction.
Avant Garde is a very exciting concept but, in the absence of virtues makes creative energies degenerative and destructive. Our world is currently in the avant garde mode of wild and meaningless experimentation. Science evolves through exploration and experimentation but respects axiomatic canons. Art is not larger than the purpose of Creation and life to disregard these rules.
See what disrespect of art principles has done: Art is now an industry, a skill, a trade, a way to satisfy greed for fame and money, a stock for trading, and an object to flaunt in living rooms of the rich. Art is now motivated not inspired. Why otherwise are artists promoting and marketing art through agents? Where have the true critics with right sensibilities gone? Why, every random purging of the mind and bizarre expression, which even the artist is confused about and cannot explain, is being seen as original and abstract art and selected by curators for best museums and galleries in the world?
To purify, heal, and restore art to its true nature... people in the art realm will have to find the clarity and courage to redefine what is art and what is not art. Canons need to be re-established to evaluate art and teach art skills. If the misguided evolution and creative work of the modern and contemporary art eras is not passed through such a restorative process any traces of true art from those periods will be soon lost. And above all, the process of human art will be lost.