Your article seems to concur.

You have to wonder if we’re seeing the re-emergence of a preliterate or postliterate musical tradition alongside the literate tradition in the early 21st century. There appears to be no noticeable diminution of composers writing detailed carefully notated scores for traditional ensembles. Instead, we seem to have the emergence of additional non-notatable musical traditions, often involving computers and electronics in addition to the traditional types of music-making.

Rather than an “either/or” situation, this suggests a “both/and” musical culture. This was predicted by Leonard B. Meyer in his 1967 book Music, the Arts and Ideas in which he correctly forecast a “fluctuating steady state” in which many styles and traditions would exist concurrently in contemporary music without any particular one supplanting any other.

“A multiplicity of styles, techniques, and movements, ranging from the cautiously conservative to the rampantly experimental, will exist side by side… past and present will, modifying one another, come together not only within culture, but within the oeuvre of a single artist and even within a single work of art.” [Meyer, op. cit., pg. 209, 1967]

This also raises the question of whether we can even talk about composers as “using notation” if some of their pieces eschew traditional notation, while other pieces use conventional carefully notated scores. If a composer like Ligeti create tape piece as well as orchestral scores, was he a literate or postliterate composer? Such distinctions may have grown difficult to make in the late 20th/early 21st century. Boundaries twixt notated and oral (or postliterate) music have grown porous inasmuch as a live interactive computer piece can be captured in a music transcription program like Finale or Sibelius and notated traditionally — albeit entirely after the fact, and as a tangential act to the original electronic performance.

We should also add the social aspect of composing as a reason to create new music. New compositions often represent a form of conversation in which one composer adds to or comments on the work of another. This process builds on itself in a socially organized way to generate a collective elaboration of a particular musical style or contemporary music trend.