The most obvious examples I can think of are Queen, Rod Stewart, Brian Adams and Genesis. It seems like there was definitely a cutoff where rock stations no longer played new music by Queen, Rod or Adams, despite the fact that they may have still been charting singles. That persists today, in how these acts are represented on classic rock stations. I don''t really recall when "rock" stations stopped playing Rod, but I seldom hear anything from the 80's or later on classic rock stations. Maybe some stations program "Young Turks. Locally, "Tonight's the Night" is the latest that gets played. With Queen, Under Pressure seems to be the cutoff for classic rock stations, though I do remember "I Want It All" getting rock airplay when it came out, which was probably the first Queen song since Under Pressure to do so. Genesis is the odd man out, as their Gabriel and quartet stuff was really too esoteric for much radio play at all. Meanwhile the Collins led trio "rocked" enough that they were able to garner both rock and pop airplay. Other examples, other thoughts?