Everywhere I read (including multiple US media outlets) blamed the low ticket sales and fan interest on the promoter and high ticket prices, not the city itself. Maybe there are some who will blame the field on Winnipeg but any educated person will realize it's due to the goalposts.
Overall, it was a horribly planned event. All the talk of pre-game festivals and making it an "event" was just hot air and despite a promise that the starters would play, the only ones who did were the kickers. The NFL and NFLPA signed off on the field yesterday and this still happened. I'm not surprised the Packers balked at it though, even if the Raiders didn't, the Raiders weren't planning on playing starters and the Packers were.