Could it be that this represents a system for generating music?

[Maruyama Toru]

Regarding the text, I hypothesize that, during this period, information was generally transmitted through oral tradition.

In ancient Egypt, when the concept of musical notation had not yet been developed, music was indeed passed down orally, but also through written sources (I know very little about this, sorry). 

In the Middle Ages, there were already musical notes and musical theory. Manuscripts containing musical instructional materials are known.

Therefore, the content of this manuscript might consist of symbols intended to facilitate such oral transmission.

This is similar to shorthand. But usually, what was passed down orally was simply written down.

one cannot learn music theory solely from texts—it requires direct guidance and critique from a master.

What does this have to do with the two previous statements?

In other words, the very fact that the text is difficult to decipher serves as further evidence that it relates to musical composition.

No... Not all complex ciphertexts are related to music, to begin with...

I do not believe it is a form of shorthand. The Voynich Manuscript was likely not written at such a high speed.

The Voynich system relied on a combination of symbols and oral instruction from a master. Today, both an instructional manual and guidance—in the form of corrections—from a master would be necessary. In other words, it is not just about the text itself; a master is essential in either case.