I've wondered that myself.
I've wondered why the Atlanta radio market has been so afraid of Adult/Variety Hits (today's equivalent of pop oldies, but centered on the 80s and 90s). IIRC Journey 97.9 did respectable for a translator signal.
I've also noticed that small-market CHRs take more chances. One good example was when 97 WFOX was still in Gainesville and hadn't moved in yet. They took more chances with the playlist than Z-93, with a deeper playlist with more recurrents. Ditto for Wide 107. Go to any smaller market and it's the same.
Then, when Fox moved in and later flipped to oldies, the running gag was "Good Times and Eight Oldies" due to a very narrow playlist. Meanwhile, oldies stations out on the metro fringe like Lake 102 and Sunny 100 played a much more diverse playlist, and a newer one to boot going deep into 1970s AM gold. I'm sure they all flipped due to the format aging out and not bringing the ratings (plus the new owner simulcasts Latino on both stations), but it does show how small-market stations seem to take more chances.
I remember there was a great oldies station, WWFN Fun 100 in Lake City, SC. Again, the more diverse, more chance-taking playlist. Later they sold out to Cumulus and are now 100.1 The Fan with sports off the bird. Probably cheaper to run and easier to sell. But at least they didn't have to change their calls.