"This is logical, because since 2001 Scrum has been widely adopted and the world has gained a greater understanding of Scrum."

I don't think it is logical. The authors of the Scrum Guide are not "the world" - they are two individuals who claim to have experience and knoweldge of what kind of role is needed. But their large number of huge swings in this role definition shows that they don't have a clue.

Fundamentally, teams need positive forms of leadership. (Leadership is influence.) The Scrum Master role is a specifically-defined up front leadership role. The fact that it is so precisely defined up front is already a red flag. The fact that the role keeps changing so drastically shows that the Scrum Guide is not worthy of being followed by anyone.