well, let's also clarify that genres don't exactly ever "die" - hell, baroque harpsichord music is still goin strong lol
the problem with rock is that it is no longer "cool" and i don't mean as a function of those who already find it or realize that it is cool. it just simply isn't hip anymore and hasn't been for more than a decade. post-rock has taken over that mantle purely as a function of the social movement it sorta accompanies and because it features a similar set of instrumentation, it works
but it isn't rock, not like zeppelin rock or anything. music, in terms of being a buzzworthy medium, always does best when it correlates with a social movement of some kind and that is usually something defined by a very specific age group (12-20); they define what's cool, the slightly older kids are the ones who make it for them and push it through their influence and the yet older kids (say, my age group somewhere in the 30s) are the ones peddling it for the guys even older than us who are making bank off it. when grunge was all the rage (when i was in that 12-18 cut of life), there were countless faces far up the age totem that i had no idea existed that were peddling the shit out of acts like pearl jam and nirvana. was that the last great era of rock? opinion wars commence! haha there's been much more impressive metal since then than there has been straight up rock n roll but that's mostly due to metal's underground affinity and how that fits well with what made old school rock cool to begin with. mainstream rock simply hasn't been cool since, in my opinion, jack white was first doing this thing
it may still come around but as of right now, it just doesn't appeal to our present young generation's #coolstuff standardbearers and therefore carries no value to young talented kids looking to make it musically.