When I went to university, my music professor bemoaned the state of contemporary music. He said there was a definite sound to the music of the Baroque or Classical or Romantic periods. With just a few notes one could say oh that is a Baroque piece or that is a piece from the Romance period. But he said that was difficult to do with modern music. Every few years someone comes up with a new innovation and music changes once more. Stravinsky gave way to the likes of Mahler, who in turn gave way to Philip Glass. Even in terms of modern popular music has had so many styles over the past fifty years: jazz, rock and roll, punk, disco, new wave, heavy metal, rap, etc. Nothing seems to last all that long.