The separation of powers is as important in academic publishing as it is in government.
If readers are to trust the integrity of the editorial and peer review process, editors need to be insulated from the business of publishing, which often means keeping them away from their colleagues in marketing, sales, and advertising.
So important is the separation of powers that some publishers physically separate editorial offices from business operations and place them in different cities. If they can’t separate these divisions physically, they will often develop strong internal policies to minimize influence. For example, PLOS does not disclose to the editor whether a submitting author has applied for article processing fee assistance when reviewing a manuscript.
Similarly, many publishers have explicit rules that prevent editors from handling their own paper or the papers of authors very closely associated with them. None of these separations of roles and powers guarantee that the decision to publish is entirely free of bias, but they do demonstrate a seriousness in building an institution, a process, and a product that can be trusted.