Is it the music that is dead, or the radio? I'm in a rock cover band, a prison ministry band, and I have a recording studio (small one) in my home.
I don't listen to the radio, except talk radio from time to time, and I haven't had TV in my home since 1997.
Rock has certainly survived as a "popular" form of music longer than Big Band did. On the other hand, the real difference between the two is that one is Brass instrument based and one is Electric Guitar based. Of course, rock has become so generic in it's definition that some would call Disco music "rock." The Cars and Devo could be called Rock, yet they are mainly synth music, as was ELP.
Byt synth based bands just never really caught on long term. Synth augments all sorts of music, even classical as in Rick wakefields "journey to the center of the earth." I had to buy a second copy because I wore the first one out (true story).
So, what IS rock anyway? Is Linkin park rock? Is Blondie rock? Is Sawyer Brown rock?
I am waiting for something to replace rock like rock replaced Big Band. But I wonder if it will happen. The reason is that the whole music thing is way overblown.
It is not about rock or the radio. It is about being able to record and market a sound to the masses. And maybe THAT is what is dying. Since anybody can record high quality music with less than $1000 of stuff, and good musicians are a dime a dozon, it has lost it's luster.
"Music of the Masses" is no longer relevant, which is how it has been for virtually the entire history of man. For a brief glimpse of human history, someone came up with a way to record a single performance and sell those recordings to the masses. A marketing empire and culture grew up around it. The pinacle was pre-pubescent girls screaming at the Ed Sullivan show, and Woodstock.
Our culture is more mature now. There are other things to spend our time and money on, as there were before the first cylinder was etched with it's inventors words.
Music is being shuffled off to where it belongs - live performance and where needed to distract - elevators and car interiors.
But it was a fun ride and spawned the invention of a lot of really cool stuff. Cool until we tired of it.
I think it was Rick Wakeman from Yes who did the 'journey to the center of the earth.' I agree with much of what you are saying and perhaps a new sensibility in rock will come from new instruments... like what keyboards did in the 80s to produce the new wave sounds. Horn based bands have gone by the way as you have said (not that they are totally dead) and maybe rock will become outdated, but like horn music still supported and studied in schools (for example, classical music and jazz are still studied in the universities). Once rock becomes institutionalized and studied to death it will have lost its bad boy, joi de vie, fuck you attitude... in other words, pop culture eats itself and rock becomes a museum or mausoleum piece. One way rock can still be alive in the future is to breed with other musical forms and create hybrids. It has done it in the past and Rick Wakeman is a good example of a rock musician that comes from a classical background... the progressive bands of the 70s was rock breeding with classical music.