The idea that it won't take much is the same idea the league itself has, and yet everyone largely agrees that the league sucks at marketing. It has a long history of sucking at marketing, and it's easily the number one area where the league must improve. The prospective Atlanta franchise should forge its own path, maybe even take cues from how Vegas and Seattle markets to their fans, rather than take cues from the league.
I totally get being optimistic, largely because optimism and positivity is my natural state. But I've also learned over the years that there's also being realistic, and you can't let optimism run wild. The reality is, no matter how many 30-somethings are here and willing to drop four or five figures on season tickets, you still need an amazing marketing team to attract the folks who aren't already fans of the sport. You ensure survival by growing the fanbase.
Apathy will definitely be a problem as well, and something that proper marketing can also address. I know several such fans. I know a few who got angry at me, even one who used to post here, that I'd even suggest the league would ever return to Atlanta. I sometimes wonder how that guy is doing. Another guy sold me a number of old pennants from the 1970s or so -- California Golden Seals, Quebec Nordiques, and an old Red Wings pennant -- after the Thrashers left town. He was part of the Thrashers organization and had no desire to even follow the sport anymore.
A lot of folks who saw two teams move had their hearts ripped out after the Thrashers left town. Some of them still follow the sport, and might be eager to adopt Atlanta 3.0 when a franchise is finally announced. Unfortunately, like the guy who sold me the pennants, some do not. If there's any hope of bringing them back, it's gonna take a lot of work to accomplish that feat.