When I was studying literature, in High School and at the University, we had a very clear line between was constituted classic confirmed quality literature and what was, as one of my professors called it, entertainments (his quote was “Moby Dick is a novel, the rest are entertainments”). I recall my junior and senior High School English classes have a California State Board required ciriculum and at the same time extensive lists of more entertaining but still acceptable works.
So as a Junior I read Moby Dick, but I also read Lord of the Flies for extra-credit. As a Senior I read Hamlet and Oedipus and The Vicar of Wakefield, but also Battle Cry and Tom Jones and The Prize. It might be characteristic of the college English classes I selected but I never had time allotted by the teachers to read entertainments (those were for school breaks and summers on the beach).
The first time I noticed that there was some softening of the divide between literature and entertainment was when I was asked to write a paper comparing Tiger Mann to Mike Hammer … at the university? I’ll have to confess that I earned cigarette money ghost-writing a theme paper here and there: I even got an “A” on one paper comparing Manchild in the Promised Land to The Autobiography of Malcolm X, which was amazing since I hadn’t read either book at the time).
Many years later when my daughter went off to college I enjoyed poking around the bookstore to see what English students were now reading. Of course there was Shakespeare, Joyce, and Milton, but there was also many classes that relied on what I would call contemporary literature if not out-and-out entertainments. I was dismayed at the predominance of so many amusements that had been written long after I left the halls of ice-plant and especially shocked at the level of slang and obscenity I found in so many of those works (not really). I guess that was another barrier the generation that followed me successfully overcame: I can’t imagine my younger self discussing the symbolism of a blow job in a mixed literature class. Damn! The Scarlett Letter was tough enough to get through with Sherry sitting beside me winking seductively (we dissected a frog together in Biology once and she was so cute when she pointed out the gonads).
In Mary Gaitskill’s novel, Two Girls, Fat and Thin, there is a passage that brought this evolution of teaching literature to mind. I quote:

… he talked about the school and the English classes which he taught. “You go to most English classed today in the school—have you? Well you should. Because you’d be shocked at what they teach. Joyce, Kafka—horrible stuff about people’s lives being destroyed by a baby crying. Or going to a carnival and getting lost and not being able to find what you wanna buy and getting depressed.. Or a guy turning into a cockroach—it’s unbelievable. It’s all about defeat and helplessness. No wonder kids hate it.”
Justine started to argue for the intrinsic value of beauty in writing, but as he continued, she found herself seduced by his blunt sensibility, so full of feeling yet so dumb, by his cheerful way of going after literature like a dog would a bone, snuffling, turning, chewing, genuinely enjoying it, provided it conformed to his belief. She thought he was a very nice person.
“What I teach is stuff like Ian Fleming, Mickey Spillane, Jack London, Hemingway, Conrad, and, of course, Anna Granite. Literature with clear plots, clear cause-and-effect connections, plenty of action and heroes. That’s the most important thing. Especially for kids this age. Heroes who live by clear values.”

Hemingway? You’ve got to be joking!
If you read the entire novel, you might want to substitute the name Ayn Rand (Alisa Zinov’yevna Rosenbaum) for the fictional Anna Granite. Let’s see, Stalin means “full of steel” … I wonder if Rand means “full of granite”?