Not the average writer doesn't begin to cover it.
I was incredibly fortunate to have experience in the traditional model. The industry was always looking for "the next big thing" without having any idea of what that would be and who would have written it. For authors, it was much like reading minds.
Additionally, there were few people around willing to teach authors that publishing is first and foremost a business, and more often than not quality is sacrificed for commercial viability.
I've done editing, copy writing, proof reading, professional advice, marketing, seemingly every facet of the publishing gem.