I'm convinced that some composers would have been far better off without the influence Boulez, Cage, and their ilk
But what "ilk" could that possibly be? Boulez is about as far from Cage as Pergolesi is from Varèse!
who compose musical snake oil for adoring zealots
I don't think that Cage was so self-aggrandising by nature as to do anything of the kind, frankly; as to Boulez, are you really seeking to suggest that
Répons,
Dérive II,
Messagesquisse,
Le Marteau sans Maître and, above all,
Pli selong Pli are "musical snake oil" (however that can or cannot be identified and defined) written deliberately and solely to be listened to by a tiny côterie of like-minded peers only? and, if so, how do you account for the fact that, given all the changes in music since the 1950s, they're still being performed today?
Progressives take note - having an open mind does is far different than having an empty one to be filled with "vampid progressive abberations of "beauty".
What's vampid? How do you define "progressives"? How do you define "beauty" and aberrations[sp.] thereof".
On top of all that, just how widespread and pervasive is the influence of Boulez today anyway?