In that case, if you are called to write and fail to write that for which you are called and gifted, are you not a little like Jonah? Jonah was called to take the word of God to Nineveh, but kept getting side-tracked. God had a plan for what he wanted Jonah to tell the Ninevites. Someone may need to read that story you keep putting off until a better time comes round. Your story may not make the New York Times bestseller list, but your story may make a difference in another person's life. What you wrote even make a difference in your own life.
You'll never find out until you place yourself before a keyboard and start typing.