I've been thinking about this thread a lot. On one hand, I love rock music! I think rockism is a great ideology! The only problem with rockism was its hegemony, i.e. there weren't other outlooks and value hierarchies circulating in the music crit economy.
On the other hand, if I think abotu the rock music I've loved, over my life, it's almost exclusively hybrid form. Hyphen rock. The Who, or Led Zeppelin, or The Strokes, those are all fine bands but... how much do I really care for that middle-road rock /classic rock sound? Not much. Rock'n'roll, especially OG Fats Domino, Chuck Berry territory—that's a different conversation.
I think talking about rock is hard because it's about as broad and indiscriminate a designation as "pop." Its diaspora probably makes up about half of music recorded in the 20th C.