You don’t want to have to convince people that they should care about your idea. It’s much better to be convincing them that you have the best book or product on an idea they already care about.
A lot of people might be like, ‘OK, we worked on positioning for a week—let’s move on and start executing!’ But I will sit with it for six months, or a year—however long it takes for the idea to feel like it’s fully formed.
But more specifically, a lot of the work early on in a book is about positioning. Positioning the product, packaging the ideas, figuring out the right frame, so that it's something that people will be interested in.
In short, his process is all about figuring out where his readers currently are—what resonates with them, what they care about—and bringing them where he wants them to go.