Nice to see this thread revived.
I had a lot to say, but then Errikos said 99% of it much more eloquently than I would have.
The 1% where I disagree might be due to my own ignorance, but I will come to that later in this post.
First, the key point of my OP (and one that Errikos embellished incredibly well) was that training Music theory and inner hearing (most important!) create an entirely different type of composer which is impossible to match by just playing with keyboards and software. The brain the the most sophisticated sequencer. The evidence for this is abundant in the quality of works as Errikos elaborated.
Having said that, there are other types of music, although 'lesser' in complexity than art music, that have validity as they come purely from the heart....a means of human expression, that somehow moves the audience as they relate to that at an emotional level more than they would to Rachmaninoff or Beethoven. Although I dont appreciate the 'lesser' music myself, I have come to accept its existence as a fact of life and tried to be more inclusive of my friends who enjoy 'lighter' music more than art music. Everything has its place...
Now the point where I - not quite disagree - but would rather like to put forth a point in response to Errikos's comment about Jazz being less complex than Classical, can be best illustrated by an example.
In a documentary about Art Tatum, they talked about how Horowitz once spent an entire 2 weeks developing variations of Art Tatum's 'Tea for two' . Horowitz then played this in front of Tatum, following which Art Tatum sat on the piano for 10 minutes and blew Horowitz's mind away by creating incredibly complex harmonies that Horowitz couldnt conceive in two weeks! Horowitz wasnt a composer but still...this was very illuminating.
But AFIK early Jazz musicians did study Western classical and were influenced by it, besides gospel and the blues, and the complex rhythms the slaves brought from Africa. I dont think they derived the harmonic theory entirely on their own. I see Jazz and Blues, the root of most 20th century western popular music, as a collective contribution of many cultures, but strongly rooted in African American music, which was the most essential part.
That was my ignorant 2 cents.
Anand