Good article by Louis Menand about Donald Barthelme in New Yorker this week. But in the interest of the biographical profile Menand sort of skims the literary-historical issues. He's genial that way : the calm relativist explainer, the generalist table-talker. About "the idea of aesthetics" (as something fundamentally conceptual, & optional) rather than simply aesthetics.
According to Menand, as long as there were standards, there was still a distinction between art & non-art, art & commerce. So-called high art could absorb low art, & vice versa - & there were interesting crossovers. But with Warhol & many others, gradually there were no more standards, no more distinctions. Whatever passed for art, was art. Menand, diplomatically, seems to offer no judicial opinion here.
Modernism occupies sort of a snowbound peak, between Victorian Popularity (Tennyson, Kipling, Longfellow) and Postmodern Popularity. Rejecting the former, defeated by the latter. But the elitism of Modernism was based on an idea of the aesthetic in which the commercial has been refined away (read, Flaubert, Baudelaire, Mallarme, Rimbaud). The aesthetic impulse is, rather, something so universal & basic (a Kantian category) that it requires no PR, no middleman. Eliot's notion of the "permanent" captures this perfectly. Indeed, Kant captures this perfectly (Critique of Judgement) in the idea that our aesthetic judgement is instinctive. We are drawn to the beautiful naturally. It's not a question of the intellect or the will. Hence the ease with which mediocre art succeeds - it wins people over with a mere (but clever) gesture toward the beautiful.
Taste = informed, educated instinct.
Modernism set itself up for this defeat. In the process of self-purification, it became its own idol (endless Borgesian mirrors of self-reflexive processes). It lost touch with its roots in unrefined experience.
The problem with the postmodern rejection of this distinction (between beautiful & ugly, original and imitation, real & ersatz) is that it denies both the instinct for the beautiful, and the critical-creative process by which art flows from it (the beautiful), & crystallizes it (in new forms, art works).
So, in a sense, neither modernism nor postmodernism was fully successful. Stevens : "the imperfect is our Paradise".