Protecting art from thinking
There are a lot of reasons to reject the high/low art divide. Here's another:
When we mark something as low art, we make it so it won't have to be considered seriously. Even if it's a big part of our world, our culture, our lives, the designation acts as an exemption: it's not serious, it's just a guilty pleasure/trashy pop.
Of course, part of what makes low art low art is that it gets to operate under the guise of unseriousness -- it's not literature, it's fiction; it's not cinema, it's a movie; it's just TV, a commercial, a plot boiler, a bit of kitsch -- but it's precisely because these things are protected from criticism, free from careful consideration or a sense of self projection and responsibility that they're so valuable to analysis. This is what might tell us most.
It's impossible to imagine, by comparison, that an archaeologist wouldn't look at the sewers of old Jerusalem. Or that an anthropologists wouldn't want to know how food was cooked in the fertile crescent, or kids entertained on the trip across the Alaskan land bridge.
Interestingly, though, the high/low divide that protects low art from serious consideration doesn't, in the reverse, guarantee that fine art, high art, or the classics are thought about in any thorough way. It should work like that, but doesn't. High art, given that distance, becomes a mark of taste and class and actually can't be discussed but only praised. Discussion, if you do this, is mere iconoclasm, or else you have to preface everything with declarations of fealty to the masters.
Maybe this isn't true everywhere. Art, the capitalized kind, the kind that tends to be modified with "great" and "fine," tends to be a middlebrow pretension in contemporary America, and one surrounds oneself with Rembrandt and Bach, Rodin and Chopin, T.S. Eliot or Shakespeare not as a challenge, not as a way of opening up thinking, but just as a cultural mark or superiority. The works are put up out of reach, by the designation, put under glass, sealed away in a room, in a hush, ensconced in hard plastic.
The argument, as I've heard it, when someone wants make that division, that divide, is always, "let's be serious ...."
But the result seems to be exactly the opposite.