It is certainly not irrelevant, and it certainly is at the basis of most DAW/vst stuff. But, there are still a lot of new ideas around. And you do find some historical articles [1]. No books I know of, though; I wish I could write one :)
I suspect the high complexity and decentralization of the community's evolution leave scholars disoriented. It is the same story for the music being made (with these same tools) itself; the genres exploded around 2000, and most popular music histories speak more of the Beatles than the last 25 years.
And a final point: these new tools (and again, the resulting music itself) are sometimes brushed aside as 'low brow' in academic electronic music circles.