My understanding is that "facts" can't be copyrighted. If there's only so many chord progressions that people find pleasing, and music taste is universal and we're born with it, wouldn't that make music more "fact-based"? Everyone will, more or less, agree on what is a pleasing progression.
I agree with everything you said except for the last sentence
You can orchestrate almost any progression to be pleasing or interesting - as there's far more to harmony than just choosing what chords go in what order
Chord voicings and the arrangement of the composition have far more of an impact on the final piece than just the ordering of chords
It's also very culturally relative - Classical North Indian harmony would sound awful (IMO) if you used more than one chord (in their case a Shruti box drone) under the piece
In a similar way, Jazz Musicians would insist the ii-V-I progression is the most useful of all time, not I-V-vi-IV like most pop/rock listeners
It's all relative to context and I-V-vi-IV is not as "universal" as all those magazine articles and blog posts will insist
Don't let the theory of harmony proposed by Bach and his dead German associates be the be all and end all of harmony
Some progressions are more popular than others (think of it like Sloane's Gap in mathematics), but there's certainly no teleology in music or its progressions!
The assumptions you make are incorrect. And even if they were, your conclusion is also incorrect.
Copyright does not require "pleasing". Only that the work have a minimum of human creativity. And courts have rules that is very minimal. Arranging otherwise uncopyrightabable facts can be enough.
Copyrighted works don't have to be unique, but it'll be real hard to prove independent invention.
I would check these premises. It was thought that harmony was universal until it was discovered that it wasn't. Then we thought octaves were universal, but apparently there were some tribes that didn't make the association. There's a lot that we're born into, but not necessarily born with.
An example of fact exhaustion is canons. They've been done a while, but there's been a lot of music made since when.
