I think Houston is clearly a viable fallback if the Coyotes do fail. Tillman Fertitta owns the Rockets, the arena and is a billionaire several times over.
The thing that's interesting about Arizona is that the arena location, which has been mischaracterized as being in the middle of nowhere, is booming right now. Houses, apartments and jobs being built everywhere. Huge new entertainment complex being built 1/4 mile from the arena and new casino hotel in the ground 1/4 mile in the other direction. Still an uphill climb but I really think if they stopped complaining and concentrated on selling tickets to the people who are close by they could easily survive. Oh yeah, a playoff team wouldn't hurt either.
The only way the Coyotes will ever get a new arena here is if it is privately funded. Aside from the Indian tribes, I just can't see much possibility of that happening. And it's a lot of money to gamble to build in a market that has two other arenas in place plus two stadiums with roofs.