It's a little late, but most books are commercial fiction. In fact, these are the books that sell the best, but they can still be well-written and beautiful. Commercial fiction is simply fiction that appeals to a broad range of people. Literary fiction, on the other hand, only appeals to a certain market of people, and literary books don't sell as well as commercial books--by a large margin. I had a professor in college whose poetry book was hailed for having an award, but her sales for that book weren't that great. They may win awards, but those awards may not make those authors bestsellers. Awards are simply ego boosts. They don't do anything beyond that.
I know some of us are here for the love of writing itself, but some of us also want to make money, and commercial fiction is where that money can be made. Of course, there is nothing wrong at all with writing literary fiction, because sometimes it can appeal to a broad audience if it's both beautifully written and easy to understand. I have a short story published in 2013: A Stellar Collection that is a contemporary literary piece. It does appeal to a certain market, however, and that is those who suffer with mental illness. Only sufferers will truly understand the characters' feelings with the metaphorical descriptions I use.
It's hard to make a distinction between commercial and literary, especially since literary books can become just as popular as fiction. From what I was told, however, literary books are purely character-driven, while commercial books can either be plot-driven or a mixture of the two. The Stars Trilogy is a mixture of the two. The other book I've written is arguably literary, but it's something that can appeal to a broad range of teens because of its subject matter.