I can remember when 80's pop-metal was never played on classic rock stations, but in the last three or four years Def Leppard, Warrant, and Scorpions etc. songs have been sneaking into the playlists. I have not decided how I feel about this change, because by accepting pop-metal the amount of blues-rock has decreased and I thought most of these stations had too much blues-rock incorporated into their playlists. Still, a typical two hours of programming is going to feature most of the same artists throughout the day: Led Zeppelin, Lynyrd Skynyrd, Queen, AC/DC, Rolling Stones, Jimi Hendrix, and a handful of others. The format runs a real risk of turning the 'classics' into 'moldy oldies'.
Classic rock is the music that I preferred as a teen, as well as a dose of country. The line dividing contemporary country and classic rock blurs more each year. I think that the natural progression from this type of rock was heavy metal, and I am exploring that genre more all the time. The worst shortcoming of classic rock is that there is never new material, a song has to have been time and road tested before it gets this classification.