There are two kinds of stories: literary fiction and commercial fiction (the kind intended solely to entertain). Why do you think some stories are considered commercial fiction? A lot of "literary" fiction is still entertaining. Is "A Dangerous Game" an example of commercial fiction?
The sad truth of the matter is that publishers are out to make money. They are BIG fans of commercial fiction, ... books that will SELL. Sure, sure, people still buy the classics for education and such, ... but it's only the true lovers of literature (can I include myself in there?) that will buy a new crisp copy from time to time.
This is not to say, however, that a piece of commercial fiction can't become a piece of literary fiction. Sometimes I wonder if Rowling's Harry Potter works will achieve that title someday, after (and if) they stand the test of time. It's the Twilight series that I know will never be considered literary fiction.
The best explanation that I can give for the difference between the two is that in commercial fiction, everything is on the surface. There isn't a need to discuss what's happening and what it means. It's all there. I haven't read "The Most Dangerous Game" in a while, and I have to say that I'm surprised to see that it would be called "commercial fiction," but if that's the case, I would say that it's because it's all there in the story. It is used in many English classes and that means that it could illustrate a lot of literary elements, but in a more blatant fashion, whereas in literary fiction, you have to search more and seek out the literary elements and what they mean.
Another reason something might be called "commercial fiction" is because of its use of stock characters and formulaic plot structure. For instance, if you look at The DaVinci Code, each chapter ends with a sort of cliffhanger. The characters are "stock" - evil, good guy, spoiler, etc. While you don't know what's going to happen at the end, you know it's going to be a suspenseful ride. BUT, most importantly, there's no real reason to read it again. Once you're through with The DaVinci Code, there's no reason to go back to it. It's over. You've got it. Literary fiction has something new and different every time you read. And that's why we study it.