The longer ago it was, the more the rules of an era of music get codified. You can run the four-part chorale rules like an algorithm.
But it's not just that - prior to Beethoven, composers were seen as not having some internal genius, but were praised by their ability to channel some kind of divine source of music - this view makes music pretty homogeneous for any era. I see a similar (arguably more extreme) outlook in many subgenres of EDM, the music isn't for stroking the producers ego but serves a purpose, the best can make something engaging in a hyperspecific style.
Coming from the increasing individuality in romantic era, 20th century explicitly tried to break those rules and one group explored ideas from folk music (Bartok, Stravinsky, Debussy) and another tried to form new ones from first principles (Schoenberg). In my opinion the latter group mostly failed - maybe they assumed rules come before music, instead of rules being written afterwards to describe music?
I think the "music theory" that will come to define our current era is the same kind of post-modernism that defined literature and art - bands that use different genres like people used to use different instruments, music that explores how rules relate to finished product (Serialism), how fundamentally different recorded music is compared to live performances, sampling, or the exploring artifacts of recording/production/codecs (Alvin Luciers I am sitting in a room/Steve Reichs tape loops/Paul Lanskys Idle Chatter, respectively).
What these all have in common is stepping outside of working in a singular "music theory" and instead working with "music theories". I like this, but not everyone does - this way of thinking about music can become detached from the actual musical experience leading to something like Punk, which then gets quickly subsumed by the thing it was rebelling against.
But it's not just that - prior to Beethoven, composers were seen as not having some internal genius, but were praised by their ability to channel some kind of divine source of music - this view makes music pretty homogeneous for any era. I see a similar (arguably more extreme) outlook in many subgenres of EDM, the music isn't for stroking the producers ego but serves a purpose, the best can make something engaging in a hyperspecific style.
Coming from the increasing individuality in romantic era, 20th century explicitly tried to break those rules and one group explored ideas from folk music (Bartok, Stravinsky, Debussy) and another tried to form new ones from first principles (Schoenberg). In my opinion the latter group mostly failed - maybe they assumed rules come before music, instead of rules being written afterwards to describe music?
I think the "music theory" that will come to define our current era is the same kind of post-modernism that defined literature and art - bands that use different genres like people used to use different instruments, music that explores how rules relate to finished product (Serialism), how fundamentally different recorded music is compared to live performances, sampling, or the exploring artifacts of recording/production/codecs (Alvin Luciers I am sitting in a room/Steve Reichs tape loops/Paul Lanskys Idle Chatter, respectively).
What these all have in common is stepping outside of working in a singular "music theory" and instead working with "music theories". I like this, but not everyone does - this way of thinking about music can become detached from the actual musical experience leading to something like Punk, which then gets quickly subsumed by the thing it was rebelling against.