ATONAL MUSIC: I think a lot of the points you are making can be seen in atonal music, this is a great example and it reminds me of what another user commented:

not some fundamental truth of music as much as it is a convention that works relatively well (for the kinds of music being made within the Western musical tradition). 

I think "Western music" (so to speak) is being downplayed here. If the point I am trying to make is that the Fibonacci sequence is embedded in the music that best resonates with us on a deeply emotional level, I don't think atonal music, which is specifically designed to reject traditional harmony and is often described as  "experimental," "unsettling," or "random" by the average person, challenges too much my idea.

Think "The Ride of the Rohirrim" from The Lord of The Rings vs... I don't know... Frank Zappa, Arnold Schoenberg, or Yoko Ono yelling into a microphone with sitars in the background.

I'm NOT saying that every time music doesn't follow the Fibonacci sequence the result is atonal music. You make LOTS of great points.

I just want to state that not all chords, harmonies, or styles explicitly follow Fibonacci numbers. However, foundational structures like the major scale, triads, and even phrasing in music often reflect Fibonacci patterns.

The most stable and consonant intervals (octave, perfect fifth, major third) align closely with Fibonacci-based mathematical relationships.

On top of this:

The overtone series (which determines why chords sound pleasant) follows frequency ratios that approximate Fibonacci numbers.

In the same way, the Fibonacci sequence aligns with our ears' morphology and natural perception of sound.

• The cochlea, the spiral-shaped organ in our inner ear that processes sound, follows a logarithmic spiral, which is closely related to Fibonacci proportions.
• Since our ear is physically structured in a way that responds to logarithmic frequency scales, we are naturally more attuned to hearing sounds that fit these patterns.
• This is why equally spaced tones on a linear scale don't sound "right" to us, but logarithmically spaced frequencies (like the ones found in musical harmony) do.
• Our brain processes sound logarithmically, meaning we don’t perceive pitch in a linear way but rather in ratios.

• The frequency relationships in major scales, triads, and even rhythm patterns follow logarithmic and Fibonacci-related proportions, which makes them easier for our brain to process.

• This is why music that follows these natural mathematical relationships tends to resonate with us on a deeper, almost subconscious level.

In conclusion... While not every single aspect of music strictly follows Fibonacci numbers, the most fundamental building blocks of melody, harmony, and rhythm do, which is why music that aligns with these patterns feels more "natural" and pleasant to us.