Publishing is what you do after youve written a book. It has to come after the actual writing process, which sort of puts it on the back burner for any writer or author whose book is still a work in progress.
No matter what you write, you do have an audience and they will read your book if you put it out there and promote it effectively.
But ultimately, the quality of the book will have a direct effect on how successful it will be following publication. I doubt that any writer will disagree with stressing the importance of this step in the publishing process --- the writing is arguably the heart of everything when it comes to publishing your first book. This is the step that will likely take the most time, care, inspiration, editing, skill and talent.