I DO NOT believe AT ALL that lost hits, even if rarely played are such a major tune out that ratings will crash, if played. I am not asking for a radio station to play JUST lost hits, I am asking them to play the tested hits and to play SOME lost hits every hour (maybe two every hour). I truly have a hard time believing that just TWO songs will cause ratings to go down. These lost hits are not low charters, they are not "Mr. Jaws" type songs, they are not songs that peaked at #99, these are not "Having My Baby" type songs, these are just good songs that KRTH has refused to play, PERIOD.
I've told you before that those of us who program in the 48 PPM markets can subscribe to the MediaMonitors service that gives us what are called MScores for the play of each song in our library. Using multi play averaging, the MScore tells us when songs cause PPM panelists to leave the station. And if we see that every time a particular song plays, there is statistically significant audience attrition, we stop playing it.
Your "lost oldie", which is just another term for a song that we don't play normally because it did not test well, will always cause fairly high audience attrition. I know because I have had to fix stations that wanted a larger library for "variety" and thus were including a lot of those "lost oldies". You could tell which songs those were from the MScore. When checked against the station's music test, I'd see that the songs were low scorers that should not have been played. When nuked, the stations' ratings always went up.
One thing is for a morning show to play one "dreaded morning oldie" each day (generally an edited short version) and to have fun with it. Another matter entirely is playing two an hour, which is nearly 20% of a station's spins, every hour, every day. That's a formula for the immediate killing of a radio station.