Re: My proposed "Music of the Future"
Jazz tends to be harmonically complex because of the use of 9th/11th/13th and the frequent sharping or flatting of individual notes in a chord. The latter includes augmented and diminished chords, which are certainly used in pre-20th century classical music but not all that frequently, but also stuff like flat 9s, sharp 9s (which is what I think of as the funk chord), and a slew of others.
Here's the one twelve-tone jazz piece I know. The main row starts after a 9-second-or-so intro. I don't think the solos have much to do with the row specifically or serialism in general but I could be wrong.