I'm not really the person to talk to, especially about music, but when it comes to generations, my experience that if something was good enough then, it can be good enough now ("now" always moving forward across time).
Look at your avatar - Darth Vader. That was big in the 70s/80s, for Gen X. As a Gen Y'er, it was big in my childhood as well, helped by the re-release of Star Wars in cinemas in the mid 90s. Is Star Wars big with kids today? Yes. Absolutely yes. I don't know how Gen Z or Gen Alpha are introduced to Star Wars (films? Cartoons? Other?), but it's still big. Something like Star Wars can stand the test of time across generations.
Pokemon is another example. That came out for Gen Y, in terms of time of release, and intended audience. Pokemon was huge - so huge that I and others began bringing our Gameboys to school, where we'd play in the playground and all that. Is Pokemon big now? Well, given that the anime and films are still going, that the games are still being released, that the JGN sections in libraries are clogged with pokemon manga, I'd say...yes. Yes it is. Given that pokemon appeals to us for a number of reasons (young children empowered, cute creatures, need to catch 'em all, floating continuity, etc.), it's easy to see why it's still around.
Neither of these are music examples, but I can't comment. Not because music of Gen X is foreign to me, just because I've never been a music affecianado. As in, I couldn't really discuss the history of music outside broad generalities (e.g. Classic to Romantic to Modern periods), and I couldn't name that many bands. But I figure that if the above analogies hold true, then if music is "good," then music will still be listened to. If anything, it would be easier now to track down music than it was pre-Internet.
Like I said, not really the best person to talk to, but at least in the scope of books and films, some things stand the test of time, some don't. Children will generally gravitate towards the material that did stand the test of time, and usually stuff stands the test of time for a reason. Again, with books, kids are still reading Harry Potter (big for Gen Y, still big now). Y'know what else they're reading? Nancy Drew, the Hardy Boys, and Enid Blyton.