That was the same appeal that Dusty had. If you check out his NWA World Championship runs, they were very brief. In his three reigns, he only held the title for 107 days, and one of those was only 5 days.
It's also good to remember that the NWA in those days was a heel-dominated promotion, a reverse of the WWF. In the case of the NWA, they had a face factory to constantly send new opponents to Flair (WWF had a heel factory to build up opponents for Hogan). Now, in a case like 1989 where Flair went from being a heel against Steamboat to face immediately thereafter when he was attacked by Terry Funk, they booked him as needed to get the crowd's blood flowing. One could argue that the fans were more against Funk winning the belt than Flair retaining it.
At the end of the day, Sting is a great wrestler. IIRC, Ole Anderson was the booker during this time, and he had a more old-school approach to booking which did Sting no favors. OTOH, both Hogan and Flair had IT in spades. Both were very charismatic (Flair was obviously the better wrestler) and could keep audiences glued to the TV or to their seats. When they came to the ring, it was crowd pop city, baby. Sting, while popular, didn't have IT, couldn't have IT, but it didn't mean he sucked. After all, both handoffs of world titles in the early 90s were massive let downs: Hogan to Warrior and Flair to Sting. Both of the former Blade Runners ended up disappointing, but for very different reasons.