I don't care one iota for trying to demarcate what is and what isn't music - IMHO just a really stupid thing to get hung up about. But the point about abstraction ("The whole problem of the sound-work [...]") in both visual and aural terms I found really interesting.
Regarding the conclusion, some of the best works have been disowned by their creators at some point, so not to worry there.
PS a nice sort of anthropological/sociological inside view of the IRCAM at some specific time can be read in "Rationalizing culture: IRCAM, Boulez, and the Institutionalization of the Musical Avant-Garde" by Georgina Born.
By the way, isn't it quite silly to say that electronic music " emerged in Cologne in 1950 at the NWDR"? As if we wouldn't have electronic music from 1000 different places if it weren't for them...