Defending literature is impossible
It is not possible to come up with an adequate “defense of literature,” because “literature” doesn’t exist: too many wildly different kinds of plays and stories and poems and songs fall under that useless rubric. Defenses of specific works, or specific authors, or even specific ways of reading specific works or authors, might be possible and useful; but nothing broader than that.
And maybe we should remember also these words from George Orwell: “There is no argument by which one can defend a poem. It defends itself by surviving, or it is indefensible.”