Many (nonfiction) authors have incredible promotional and marketing plans as part of their book proposal, so why are publishers not always that impressed by them?
It goes back to that highly illogical, yet indisputable, fact of the nonfiction publishing world: Books do not build movements, movements build books.
Of course, what an author intends to do to promote their book upon publication is very important but everyone has the very same intentions and plans. To promote the launch of their book, every author plans to build a website, write articles, seek out speaking engagements, focus on building social media followers, appear at certain conferences, do podcasts and shows, and so on. And that's the problem—every author plans to do this all, and since every author cannot be successful given the competitive nature of the marketplace, it means that most authors will not really have any impact despite all their efforts.
I can have every intention of making my book a success but intention does not equal actual results. This is why to most publishers, what you have already achieved is often far more important than what you hope to achieve. How well-known and established are you in your industry before your book comes out? How often are you already speaking? And to what size audiences? How often do you write articles and pieces in major outlets and what are the readership numbers like? How do your social media following numbers look? Where has your work been featured and or written about?
The best predictor of future success is established presence, not future intentions.
Have a movement and a following behind you before you launch your book instead of thinking that your book will launch a movement and garner followers because the chances are it won't. Yes, your book is special to you, but to the marketplace, it is one of 3 million titles that will come out this year (not an exaggeration but an actual statistic based on data from Bowker—the institution that issues ISBNs for releases).
Crankily yours,