To be clear, this is just how Doctorow has always been, he's always been that annoying nerd who needs to come up with new words/phrases. Enshittification is just the one that caught one.
See also: Whuffie, metacrap, and Schneider's law. Those are all from before 2005. Like I said, this is who he has always been.
I am of two minds on Doctorow: One one hand, I appreciate his thoughtfulness and insight, and on the other hand I cannot stand how much of a weirdly pedantic nerd he is, especially when it comes to his own ideas.
Also I remember him kind of really sucking at journalism at first in the early 2000's. I recall an article about Napster where he said "Napster's original goal was to sell music to people" which blew my fucking mind because it was always meant to be a peer-to-peer network and my god, we have both lived through this era, how could he manage to get it so fucking wrong? I was especially galled because he had just been given a class to teach at UCLA while my friend who actually had a masters degree and his thesis was on the social network aspects of piracy and the co-evolution of control and resistance in computer networks was struggling to find a job as a teacher.
So due to those early memories, I may be a little biased.