WLYNgm said:
I have often heard the rule of thumb as follows:
"Oldies" are the stuff that you listened to while you were in
high school, heard 25 years later. The benchmark of what
then qualifies as "oldies" progresses along with the age of
your target audience...
Right, but the perception of the term "oldie" got hung up in association with the demographic that first used it, the '50s/'60s "oldies" generation.
Music will still always cycle back in nostalgia periodically as you mention, but people who want to hear '70s and '80s music don't want it to be called "oldies". That conjures up memories of their now gray-haired parents listening to Elvis, and the sponsors know this.