Universal Art?

There are some works of art that stupid people will never understand because they weren't made for stupid people. And there are a lot of stupid people. Why should anyone assume that any work of art can be reduced to the level of comprehension of a contemporary eight-year-old?

- Robert Hughes (from this interview)

Paula Rego, Girl Lifting Up Her Skirt to a Dog

Many consider Hughes the best art critic in the world. This is his most famous and witty book about contemporary art:


In the preface, he asks: "What has our culture lost in 1980 that the avant garde had in 1890?"
And answers: "Ebullience, idealism, confidence, the belief that there was plenty of territory to explore, and above all, the sense that art, in the most disinterested and noble way, could find the necessary metaphors by which a radically changing culture could be explained to its inhabitants."

The thought is impressive. It inspires to lift one's butt and find those necessary metaphors.
But I have some doubts. The idea that art should "find metaphors", and that they are to be the "necessary metaphors", seems both scary, and distant from a modernist perspective. Conveniently, Hughes gives the example of the Eiffel Tower, which was not, however, your typical artistic enterprize of the time. Of course, today we might see it as such, but putting it as a prototype of a work of art of that era it is a projection of our today's perspective.
Doubt #2: The Van Goghs and Gaugins, and even the futurists, were not quite the "culture". They were clearly the avant garde. And with this noble classification came a marginal social status. Thus, we cannot compare today's culture to yesterday's avant garde. Those are simply different worlds. The question might be - do we still have an avant garde? Well, did the average art lover of the 1890's know what was the true, valuable avant garde (as seen by us today)? Of course, we are not just your average art lovers. We are - us. And so we know.
Does an avant garde still have any sense? Or is art so institutionalized it's impossible to see it as this fresh, new force?
I am deeply convinced that avant gardes still exist, as always, in plural, and as always, difficult to see, maybe not as much for aesthetic, as for political reasons. The avant gardes that have prevailed (that we know) seem to be those that have been taken up by some political/social movement. And those movements are yet to come. Today's social currents pick up yesterday's avant gardes and turn them into what we know - starry starry nights and eiffel towers.