The problem with creating a new music theory is the question what do you want the music theory to do? The main value of classical music theory is exactly the historical underpinnings that you want to drop
I'm a jazz musician. The people I know who can create their own compositions and arrangements in that genre all studied theory in college.
Like you could combine a bunch of random notes together and it would sound terrible. THe reason why a certain scale is a scale is that it all jives together in a way that makes sense to the human brain.
Most people just make what sounds good to them and that creates a massive power potential to extract by labelling some of that "good" and some of that "bad" in the eyes of an arbitrary system.