While I agree with your take on the Thrashers (they absolutely were on the upswing), I see a team in Winnipeg a bit differently.
From strictly a business standpoint, The Jets have the benefit of a stable ownership, which looks good to the league. Even if the team is doing poorly, or the economy blows, or attendance continues to dwindle, the team is fine so long as TNSE wants to continue with sustained losses during a rebuild -- whether that be the team, the economy, or both.
The issues with Atlanta were great, and covered at length across several different BoH threads and news articles published over the last 12 years. If saving the face of the league meant a team had to move to Winnipeg, the league was fine with that, but it's clear the league couldn't own and operate two NHL teams at the same time.
While attendance issues might continue to get worse, the question is whether ownership will do anything to get more fans to show up. Unlike what some of us heard from some fans, hockey doesn't sell itself, and certainly not to a fanbase that is disinterested either due to financial reasons or because the team just isn't all that good/exciting to watch.