Bandwagon teams exist everywhere. Until the Preds made the Stanley Cup, they couldn't sell out a game. In fact, 8 years ago, Predators owners decided that they would move the team out of Nashville, unless they could sell out some games. Local businesses (mostly radio stations) bought up tickets to get the sell-out, and then gave them away - only pissing ownership off even more, because the fans were wearing Red Wings jerseys (I know, I was one of them).
The season after the Cup run, tickets are re-selling above face value.
At least Vegas has a sizable community of sports enthusiasts - even if their enthusiasm comes from sports betting. We'll see what happens when the Raiders make their move, but I expect a lot of excitement there as well. And when the G.Knights hit a couple cooler seasons, the true fans will continue to show, and we'll see how many hockey fans are in the desert then.