There's this joke in the movie "Amadeus" where the emperor (Joseph II?) remarks that Mozart's music has "too many notes". He explains that the human ear can only hear so many notes. That might have a element of truth. Our perception is (obviously) limited, and beyond a certain point, complexity becomes overbearing.

But on the other hand, minimal music is a much more recent development, and it is certainly part of the "classical" tradition. There might be a bit of room left before we find the end.