One line of reasoning goes: in the future the publishing industry will not be based on the purchase of individual titles, but instead on subscriptions which grant access to titles (as in Netflix for books). In this scenario a writer might have no motivation at all to contract with a publisher and instead bypass the publisher and post their book directly to Amazon or some other incarnation that offers distribution services. And so, the natural conclusion is that publishers who hope to stay relevant will need to offer some new value if they hope to be kept in the publishing loop at all. Namely customer service in the form of marketing, editing and design.
This article bumps up next to the previous argument in some interesting ways.