The greatness of literature cannot be determined solely by literary standards though we must remember that whether it is literature or not can be determined only by literary standards.
If a novel reveals true and vivid relationships, it is a moral work, no matter what the relationships consist in. If the novelisthonours the relationship in itself, it will be a great novel.
Literature deserves its prestige for one reason above all others - because it's a tool to help us live and die with a little bit more wisdom, goodness, and sanity.