So the word "classic" to which you refer (and,perhaps,subscribe) is more of a trademark whereas my use of the word is more in line with the standard definition found in the Oxford Unabridged.
I understood your use of classic, but was just pointing out that classic rock is an established musical genre, and it behooves us to understand what someone is listening to when they say they're listening to classic rock. It's not Buddy Holly or Elvis, as those aren't sold under the classic rock banner or played on the classic rock stations. You can of course feel free to use your own defintion, but you'll find that it will make communication more difficult.