Waiting for sales

It is when you have just published a book that you realize that oublishers matter - they keep the process going both before you write the book and after. By having a large number of books in the same area (at least a hundred, if I got the numbers right), they can support the project managers, sales people and others who are needed to make sure a book comes to market.
When you publish through a traditional publisher, they enter the book into their catalog, and sell the catalog. They actually do not sell the individual book. That is what you have to do if you are a self-publisher. The hard part is you made it yourself. It is like selling your children.