The mechanism worth understanding is evaporation, not immersion. An ear canal clears moisture by exchanging air with the outside; a pendulous ear leather slows that exchange down enormously, and warm saturated air slows it further still. Through an Atlanta July, there is no point in the twenty-four-hour cycle where the ambient air is dry enough to finish the job — overnight dew under a heavy canopy is often the most humid part of the day, not the least.
This breed's coat compounds the effect from a different direction. A medium, straight, water-resistant coat is built to shed rain off the outside; it is not built to wick sweat-damp air out from underneath a folded ear. The practical consequence is that an Atlanta owner should treat drying as a scheduled weekly task from roughly May through September, whether or not the dog has been near water. A quick look and a soft cloth once or twice a week costs nothing and heads off the $150-to-$300 visits that otherwise repeat.