You also have to factor in the "Want To" of the venue. The city/tourism/venue has to be willing to pony up a big sum of cash as well as provide a lot of man hours of service to get the event. Extra police, extra city workers hauling trash, buses, different things.
When setting up one of these deals, be it an Elite Tournament, a Classic, or a Major League Fishing Bass Pro or whatever, there's a huge punch list of things that have to be done, services that are needed, equipment, tools, you name it. My guess is the comfort of all involved plays a factor in it.