- The Scrum guard role may be unnecessary, even distracting
- Scrum Master may be a much bigger role than you're are considering it to be
- The goal of a Scrum Master is not to be come superfluous (adding no more value) but to find higher order ways of adding value outside team dynamics and operation.
- A Scrum Master skilled in coaching may still bring great value to a Development team and Product Owner even when they can function independently of that Scrum Master.
I want to affirm the rightness of a Scrum Master working to ensure they are not a bottleneck for the Development Team to function. Indeed, they should work to multiply the effect of the Development Team's work without creating dependence; however, this is very different from saying that a Scrum team de-coupled from a Scrum Master could derive no more value from having say, a skilled coach dedicated to them. Be careful of the Duning-Kruger here.
With respect to you and your organization as capable and independent people, I wonder if the Scrum guard role could be a distinction without a difference? If a Scrum Master's responsibilities are truly being split between two people, that would give me pause to consider the reason the distinction is being made. What value are you all getting from calling them a Scrum guard instead of a Scrum Master? Perhaps you are finding value the Scrum defender role, yet I do not see it from reading your post.
The goal of a Scrum Master extends beyond simply spreading knowledge of Scrum and ensuring events are conducted smoothly. It extends into the audacious and worthy challenge of coaching Scrum teams and whole organizations towards radically high performance. I know this to be fully within the contextual aim of Scrum and therefore the ultimate responsibility of a Scrum Master. This does not seem to me to be a job for which one would likely ever become superfluous. Unless...
...your organization is considering the Scrum Master role to be much smaller than it is intended to be. Perhaps this is why some consider rebranding themselves as agile coaches, a role that seems bigger to them.