All roads lead to Rome.
Notice that auditing firms have already expanded to become consulting firms. Notice further the considerable overlaps among the functions of consulting firms, activist investors, and proxy advisory firms. All are professional outsiders looking into a company and giving independent opinions on strategic decisions. However, to keep this shareowner-power intermediary role from getting too powerful and creating substantial agency costs of its own, it may be preferable to limit its function. For example, it may evolve so that shareowners vote to choose an intermediary that only oversees the selection of the auditor and other critical outsourced services, rather than performing those services itself.