The Lydian Chromatic Concept of Tonal Organization is a 1953 jazz music theory book written by George Russell. The book is the founding text of the Lydian Chromatic Concept (LCC), or Lydian Chromatic Theory (LCT). Russell's work postulates that all music is based on the tonal gravity of the Lydian mode.
EG: Read something like George Russell's "The Lydian Chromatic Concept of Tonal Organization" (the basis from which modal jazz sprung, which includes one of the most famous jazz albums of all time, Miles Davis's "Kind of Blue"). Now add to the theory the ability to improvise around it as good as a Miles Davis level jazz performer can. It's not technically easy at all.
Even if other music genres are much technically easier, so much of music is the social experience anyways.
Take punk music. Though some parts got more technical later, much of it (particularly the late 1970s / early 1980s stuff) is, in my opinion, very technically easy; not too challenging to play, with very basic music structure (which was half the point, a return to rock's garage roots).
I'm guessing an AI can probably be developed (especially with today's fairly realistic sounding guitar VSTs) to make some "technically correct" old school punk rock, certainly much easier than it can be programmed to make "technically correct" modal jazz. An AI, however, cannot replicate the human parts, eg the social or community aspects of a music scene. Which with a lot of music is a huge portion of the point (certainly for punk it was).
Also, a lot of jazz musicians wanted to eventually learn musical notation at least so that they could write their own lead sheets for copyright-claim purposes.
The Jazz Theory Book (Mark Levine)
Huge series of play-along books by Jamey Aebersold
The Geometry of Musical Rhythm (Godfried Toussaint)
Harmony (Walter Piston)
A Geometry of Music - Harmony and Counterpoint in the Extended Common Practice (Dmitri Tymoczko)
Lydian Chromatic Concept of Tonal Organization (George Russell)
Augmented Scale Theory (Javier Arau)