A question about canonicity of the Scrum theory - Scrum Master is a managerial position

In his 2004 Agile Project Management with Scrum book, Schwaber wrote

"This book is about ScrumMaster, the Scrum project manager who heads the Scrum project. The ScrumMaster provides leadership, guidance, and coaching. (...)"

Project manager is a managerial position.

So, given that Schwaber wrote it and it has not been changed/overwritten by the author himself (afaik), I conclude that as a theory this one is still valid. 

Now, I do respect that Scrum Org/Inc/Alliance have their own businesses and so on, that's fine, everyone wants to live, I get that.
 

I am asking about the canonicity of Scrum theory.

So if Schwaber wrote that and it has not been denied/overwritten by Schwaber himself nor by people to whom Schwaber potentially legally transferred IP over Scrum - then this still takes hold in my view.

Theory-wise, it is irrelevant what people think about it. 

What is relevant is what is part of the theory canon and what is fan-fiction, useful of not.

I don't think that I'll ever get a clear binary response from Ken Schwaber on that, thus I'm asking random people on this forum - what is the canonicity of Scrum theory? What are canons that define what is truly True/False in regards to theory, to which True/False statements you can point people who argue about theory and finally give them a finite True/False statement according to that set theory, in a way similar to a situation where you can give a True/False statement to a person who invents how maths work.

And please spare me interpretations, opinions, so on. Of course a decision maker decides on how they interpret and implement Scrum and eventually face consequences of their decisions. 

I'm interested ONLY in what I refer to in my question - the canonicity of Scrum theory. Given that Scrum Guide changed throughout a timeline - what was a foundation for that change? Was it only a market demand as Org/Inc/Alliance do sell Scrum courseware? Or maybe there was an underlying theory developed throughout years, akin to ThinkLets, Positive Deviance, or TRIZ which has been in development since around 1960'?

To quote Barksdale - If we have data, let's look at data. If all we have are opinions, let's go with mine.

So, what's and where's the data?