People like Frank Zappa and Bryan Ferry knew we could pick and choose from the history of music, stick things together looking for friction and energy. They were more like playwrights; they invented characters and wrote a life around them.
One often makes music to supplement one's world.
Something I've realized lately, to my shock, is that I am an optimist, in that I think humans are almost infinitely capable of self-change and self-modification, and that we really can build the future that we want if we're smart about it.
A way to make new music is to imagine looking back at the past from a future and imagine music that could have existed but didn't. Like East African free jazz, which as far as I know does not exist.