That store was probably Down Under, Scott passed away about 3 months ago very suddenly. That was the one shop that I would go into if I needed something in a real pinch. Aaron is still running the store to my knowledge, and he's a little weird but still a good guy. Not sure where in NC you end up flying into, but Air Hogs is a good shop outside of Raleigh, and NADCO in Greensboro is very good as well. Dolphi Graves is a great guy with a good solid technical diving shop.
The reason it doesn't need 6 is because the business isn't there to support 6 of them. If there were 3 shops in that area, each shop would have more call it 2x the money coming through *obviously the business is not divided evenly, but for easy math* and be able to stay price competitive with the online shops because even though their margin is a lot smaller, the total dollar contribution ends up being higher. You need some competition to keep everyone honest, but too much and the stores are barely scraping by which isn't good for anyone. You have the awesome big shops like DRiS, Cave Adventurers, Northeast Scuba, DGX, etc who rake in boat loads of money yet still go bezerk trying to beat each other in pricing because the businesses are going quite well and they are moving lots of gear. You need one or two of those types of places near the big dive sites but to have more than a pair of decent sized shops in a city that isn't a diving hub is just a recipe for failure.