Can I ask where it is you live to see hordes of young people finding solace in classic rock (or any sort of purely guitar-based music) ? Except maybe in US rural communities where it's all about country music (always has been, always will be) those days are well and truly over. "Nobody wants an electric guitar anymore" : https://qz.com/1013293/rock-and-roll-is-dead-sales-of-fender...
Meanwhile electronic music has taken millenials by storm. Tomorrowland festival sold out nearly 400.000 tickets in 40 minutes a few weeks ago. Same kind of numbers every year for Electric Daisy Carnival in the US.
Never in history has there been so much quality music released every day in all genres, because musicians can now do so without the gatekeepers of the past, much like Youtube has shattered the TV networks.
The consequence of that is that it's all about fragmented niches and discovery can be challenging. But there is gem after gem in my Spotify "Weekly Discovery" playlist. There has never been a more exciting time to be a music lover !
This for example: http://www.hawaiianreggae.org/artists
Nice and mellow, lots of young new artists. It's a pretty good scene.
Ask the kids what they think about today's mainstream music. They will say it's amazing. Who do you think drives the charts?
Yes, yes, I know, you are or you know a couple youngsters who think anything newer than Pink Floyd is shit. And you think that the charts are not organic, they are "marketing", where the record label pay to get entry and rank.
That's a different issue. New music really is garbage; the entire industry has changed over the last several decades. There's a reason so many younger people are listening to classic rock.