The Scrum Alliance published a survey that has some supporting evidence. Over 60% of the 1100 people that responded to the survey had nine or more years of industry experience, 15% of them had twenty or more years of experience, and 35% had Masters degrees. Also, of the people who responded, 22% were project managers and another 21% were either Managers or Directors. So my simple translation is that practicing ScrumMasters are managers (project or other) with significant (10+) years of proven experience. Training and assigning this role to experienced project managers or software development managers seems like a viable approach to have the responsibility filled and having a dedicated ScrumMaster separate from these roles may not be necessary.
