Winnipeg was about as big a loss that could have happened to the AWA at that point, in terms of losing a consistently drawing market that hadn't experienced the attendance downturn that other formerly stable cities had. AWA was already experiencing problems drawing in the Twin Cities and in Chicago, while Winnipeg had stayed steady and had even seen a upturn in the few months proceeding the WWF taking over there.
An underrated facet of the AWA dying off was the move of their TV to Las Vegas. The re-vamped TV was necessary for the ESPN show, but by moving away from the focal point of the promotion being in Minny and St. Paul, they basically conceded their home base to Vince which, in hindsight, left them with nowhere to really turn back to once Vegas was used up.
The cards were on the table by the time they finished up in Vegas, but moving back to Minnesota for their World Title battleroyal (an attempt of sorts to re-establish a home base where they could at least exist on a much smaller scale), and then drawing only 800-ish to the Civic Center for it was a sign that the home-town flavour the AWA had provided for 30 years was all but gone. 3rd-rate talent is bad, but continuity in an area where the AWA had that much tenure might have allowed for the fans to put up with it until things rebounded. Breaking the continuity of Minny as the home base prevented that from ever having a chance to happen.