When only 400 folks appeared at a rally to show support for the Thrashers, it pretty much signaled that there are not enough fans in Atlanta to support an NHL team in both good times and bad times.
Knowing someone who was at that rally I can attest that the way it was covered in Canada was embarrassing, homeristic journalism at its finest. That was never even intended to be a rally, just some hardcore fans getting together to do their own thing, but once media personalities north of the border got wind of it they were basically called out on making it a "rally" and of course they weren't going to get a lot of people on short notice. And anything intelligent any Thrashers fan said at this "rally" was guaranteed not to be reported by TSN, Sportsnet, etc.
As for whether the NHL could work in Atlanta, there's two possibilities here. To work at Phillips, ASG would have to take a hike. Could it work then? Hard to say, maybe.
An intriguing possibility to me, which someone else above hinted at, would be the suburbs, most likely Gwinnett. I think if there was an NHL sized arena there, you could almost see a situation similar to what San Jose has been on the west coast. The demographics are more in line with traditional markets (more white and middle class, as crude as it is to put it like that). For fans in the suburbs the way the transportation works in Atlanta made it very impractical to go to games unless they went directly from work.
