It highlights how little control the majority value providers actually have. Forums are mediums where information exchanges happen. When the mediums owner starts dictating what type, how much and who exchanges information then the most easily replicable, lowest value member is dictating the terms to everyone because of their centralized control.
Unfortunately while replacing them is rather trivial, due to the nature of collective action problems, it is nevertheless quite painful to orchestrate the wide ranging coordination necessary to migrate so many users in any truly succinct manner to another medium. Usually this process is messy and happens over time and requires a significant catalyst to push people over some threshold and a sustained effort to inform and educate casual users.