The definition of "classic rock" keeps changing

I came of age in a suburb of Atlanta. I primarily listened to 99X, alternative and grunge radio station. It shut down in 2008.

I went to visit family for Christmas and my sister mentioned it was back on the air but she hadn't listened to it yet. We switched over to the new frequency and they were in commercial break. We briefly wondered if they would be playing new alt rock and what bands that might include. Then they returned, playing a Cranberries song.

My sister says "oh, so it's classic rock now."

I (lightly) smacked her leg because I can't handle that truth.