Uh, have you actually listened to any of it? At all?
There are some non-Western traditional types of music I'd agree can have a level of complexity not usually encountered within the Western classical or jazz genres, but it's fair to say all over forms of Western music are vastly simpler in terms of harmonic language, tonality, form/ structure, instrumentation etc. None of which I believe would make it harder for AIs to generate, as computers can manage complexity rather well. What I expect AIs to not be good at is to conjure a truly original and distinct sound world significantly different to anything that's come before, but that still captivates audiences. Which is arguably what the greatest human composers & musicians have generally achieved, in any genre.