What is the vision of a Servant-Leader? Why is the Scrum Master the only servant-leader?
Is there anything in Scrum that suggests that no-one else can be a servant-leader?
Why is the Scrum Master the only servant-leader?
While the Scrum Guide only uses the term servant-leader when discussing the Scrum Master, I don't believe that they are the only servant-leader. To me anyone and everyone on a Scrum Team or an agile organization can be a servant-leader. Robert Greenleaf was the first to use the term servant-leader. Here is a link to the greenleaf.org site where it is discussed. (https://www.greenleaf.org/what-is-servant-leadership/). Based on that discussion others you can find on the internet, I feel that the servant-leader mentality plays a very big part in Scrum and that all are willing can be one.
What is the vision of a Servant-Leader?
This comes from the text at the link I provided above. "A servant-leader focuses primarily on the growth and well-being of people and the communities to which they belong."
A Scrum Master ought to exemplify servant leadership, and in so doing might promote servant leadership in others as well.