I take umbrage at them being called "classic rock." Classic rock is, to me, a specific genre of rock music from the 60s–80s, and it has a particular style and sound.
Throwing Green Day and Linkin Park in with the Eagles and Fleetwood Mac just makes the word "classic" meaningless.
I think we'd have to differentiate what's considered classic from genres themselves. Rock's been around for about 70 years, so it makes sense that a classic era emerged about 20 or 30 years after that. You could see it as something of a golden age of the music. Punk started in the 70s, so if you want to call Green Day classic punk (although no one really uses that term) I think it'd fit.
Similarly if someone said classic ska I'd be thinking of 2nd wave, like the Specials, which is also about 20 years after the start of the genre.
My guy, those weren't called classic rock when they were still new. They were just called rock back then.
I've been told by the kids that American pie is a country song
