As mentioned in my prior post, 50 kw on 1550 in an area with terrible ground conductivity is just not enough, even non-directional, to cover the market. And the protection requirements to the two primary users of 1550, Mexico and Canada, make night operation even more problematic. Once AM started its decline in listening, it was likely not worth the money to try to get a major improvement on this facility.
One of the few successful AMs at 1500 or above eventually had to move to FM or die: WTOP in Washington, DC. 50 kw fulltime on 1500, but it could not cover the whole market. The only remaining really successful high-dial station I can think of in a larger metro is KFBK in Sacramento, but it is 50 kw fulltime with a less restricted pattern, a Franklin antenna system and great ground conductivity. The Atlanta station has none of those positive factors.
In fact, of 520 US AM stations between 1500 and 1600, only 10 bill over $100,000 a month and of those, 3 are paid religion and one is Asian ethnic in format. The indications are that, unless you have a very very good facility (DC, Cincinnati, NYC, Minneapolis, Bakersfield, Sacramento) with decent conductivity, pouring money into a station high on the dial is useless.