Phoenix, the 6th largest metro area in the country, once said much the same thing. Now, they screwed up where they put their rink, but still. Non-hockey markets typically struggle and Vegas isn't a natural hockey market.
I would guess a good first 5 years, then things get dicey.
That's a very good point. The buzz will be there initially, but if they can't put together a contending hockey team, something the Coyotes have always had trouble doing, things could very well get dicey.