No one would expect Roger Scruton (those who know of him) to lavish praise on Boulez even in the year of the conductor/composer's death. He DOES have nice things to say about Boulez the conductor but makes a case that Boulez as impresario and polemicist, Boulez as composer, did not give us a whole ton to be hugely grateful for.
Scruton didn't point this out but I will ... most of the world didn't pay attention to the death of Pierre Boulez because David Bowie's death was considered more culturally significant the world over. Now if Roger Scruton's not happy about that EITHER, fair enough. But it's worth juxtaposing the death of Boulez and the death of Bowie to help reinforce a point Scruton has been making, that Boulez was the smiling emperor sitting on his self-established throne but that beyond the realm of his partisans people might not even know his name.
I can't recall where but I read that Boulez once declared that pop music was providing the wrong answer for the right question. If anything I would venture to suggest that twelve-tone could be taken in the same way. If the musical vocabulary and syntax of late Romantic music had devolved into formulaic kitsch by the end of the 19th century the way to revitalize that vocabulary did not lay in the biggie-sizing propensities of Mahler or Strauss but in the fragmentary re-appropriations of those chords and tunes into nascent ragtime, blues and jazz. After all, while a retrograde of a twelve-tone row may have its sound the tonal ambiguities in blues could get you a riff that could be played forwards and then backwards but recontextualized with different harmonies along the way. Where I suspect I would differ from Scruton is that while he's been less than thrilled with pop music in the last century and loves Wagner I loathe Wagner's music but would suggest that the kinds of harmonic and melodic idioms Wagner played with are more likely preserved in some fashion within the vocabulary of popular music than in even a performance of Wagner that was conducted by Boulez.
Which might do a better job preserving the grandiosity and ambition of Wagner's music for someone like Scruton? Pierre Boulez' pli selon pli? Or the Who live at Leeds?