Might it be an issue of the lack of decent AM signals in the ATL? Nobody is going to go out on a limb with local talk on FM, and nobody is going to invest in an AM daytimer.
Once you get past WSB, WGST, WQXI, WDWD, WCNN, and WGKA, there's not much left on the AM side. WSB is the 50k class A blowtorch, WGST is CC's "Rush Radio" placeholder in ATL, you have the two sportstalkers (some would say one too many), Radio Disney, and Salem's placeholder in ATL for their syndicated talk.
After that, you have, what? WNIV, which is Salem's syndicated preacher; WCFO, which is third-tier syndicated talk; WAFS (1190, Salem again), and WGUN. All daytimers (not counting their lightbulb signals at night).
There are some other unlimited signals like WFOM and WLTA, but they are too far out and too weak to provide good metro coverage.
Big radio (CC, Salem) uses their O&Os to serve up their nationally syndicated programming, if for no other reason than to get it on the air in the #7 market to help with ad buys. That also seems to be the reason for WCFO's existence, despite their crappy signal.
I could see someone turning Quixie, being the weaker sportstalker, into a local talker (reminiscent of the old Ring Radio). But sportstalk is already quite local itself. Would that really be more attractive than what they are doing right now?
That leaves WGUN. Probably the biggest waste of 50k during the day.
Now, to the NE you can look at what Jacobs is doing with the WDUN semi-simulcast...
Remember, Neal Boortz, Clark Howard, Martha Zoller, Mike Malloy, and Sean Hannity all got their big breaks as local talkers in the ATL. And WSB has Herman Cain, and tried Royal Marshall. WGST had the Kimmer and Ralph from Ben Hill, and Ian Punnett.
It also seems to me to be both an issue of a lack of talent and a lack of signals.
Please forgive the rambling but I don't see a clear-cut answer here.