The reality of writing a book is that you have to write a lot of words. You have to get your thoughts on paper or in that digital file displaying on your computer screen. You have to pull ideas out of your head, articulate them, and get them down where you can actually do something with them.
Books are made up of many, many words massaged and manipulated just so in order to tell stories. Even nonfiction books are made up of stories, narratives that bring the reader along as they inform, conjure up thoughts, evoke emotions.
Writing is art. You have to make time for writing if you want to be an author just like you have to make time for art if you want to be an artist.