If you think writing a book is a one-person job then your project will be read by only one person.
In reality, the path to publishing is a collaborative effort. In my previous efforts with non-fiction, I had many vendors supplying me information, contacts with corporate media coordinators, a technical editor, publisher editor, assistants and my personal support group.
Now that I’m knocking a the fiction world door, I have a dozen critique friends, another dozen semi-local writing colleagues, a grammar editor and another dozen friends I’ve met at conferences. That’s a good count and I haven’t entered the agent/publishing circle.
At the agent/publishing party there are your agent and her staff and probably an editor. At the publishing level you have an editor, a copy editor, printer, assistants and marketing staff.
I’m sure I’ve left out more than a few people, but I think I’ve made my point.
Writers write, but writers get published using their team.