This isn't "music theory" (although almost everyone thinks it is). This is "music jargon and notation systems". A theory is something that explains an observed phenomenon. This jargon and notation stuff doesn't explain music, it just guides you through the jargon and notation. I have a music degree and learned all this stuff and a lot more. This presentation is an excellent , high-quality overview of this non-theory…
Thank you! I've long been suspicious of so-called music theory for exactly the reasons you outline. I always wanted to learn more about music and why it "works" as you say, so I assumed what I wanted to learn was music theory, but then when I tried to learn it it didn't seem to explain any of the things I was looking for. I'll have to check out that book.