Avant-Garde of what?
Picasso the bourgeois. T.J. Clark, likewise.

That care in Picasso's case was often mixed with Bohemian insolence and destructiveness does not alter the point. For who has not grown use to the paradox that in so many of the artists who seem to us now to have spoken most deeply of (maybe even for) bourgeois society—Flaubert, George Eliot, Simmel, Manet, Marx, Menzel, Baudelaire, Ibsen, Henry James—care seems indistinguishable from distaste? Bohemia was never as withering on the subject of bourgeois illusions as the great masters of the novel. The Communist Manifesto, we see in retrospect, is as much under the spell of Adam Smith and Balzac as looking for a way to set their world on fire. It is the great poem of capitalism's potential. And who are the heroines of the new order if not those who stare its horrible decencies most fully in the face: Olympia, Madame Bovary, Hedda Gabler, Kate Croy, The Daughters of the Vicar, Woman with a Hat? Maybe belonging and not-belonging, or respectability and disreputableness, just are -were- what is meant by bourgeois identity: they seem to be (again, in retrospect) what marks off this strange way of being-with-others-in-the-world from others before and since. 

"...care seems indistinguishable from distaste", and the reverse.

"Because the interior is the truth of space—for Bohemia, those last believers in the nineteenth century."

Art is made by loving something so much you see it honestly or hating something so much you see it in its complexity.
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update. Something I remembered.
Arendt, The Human Condition

What the public realm considers irrelevant can have such an extraordinary and infectious charm that a whole people may adopt it as their way of life, without for that reason changing its essentially private character. Modern enchantment with "small things," though preached by early twentieth-century poetry in almost all European tongues, has found its classical presentation in the petit bonheur of the French people. Since the decay of their once great and glorious public realm, the French have become masters in the art of being happy among "small things," within the space of their own four walls, between chest and bed, table and chair, dog and cat and flowerpot, extending to these things a care and tenderness which, in a world where rapid industrialization constantly kills off the things of yesterday to produce today's objects, may even appear to be the world's last, purely humane corner. This enlargement of the private, the enchantment, as it were, of a whole people, does not make it public, does not constitute a public realm, but, on the contrary, means only that the public realm has almost completely receded, so that greatness has given way to charm every- where; for while the public realm may be great, it cannot be charming precisely because it is unable to harbor the irrelevant.