My guess is that casinos, with their typical delusions of grandeur and arrogance, aren't willing to concede enough (yet) to make them interesting. You don't just jump into bed with the first pig who puts on lipstick. Shareholders, and sideline quarterbacks, are all clenched up in their wish for instant gratification. Zynga is playing the long game. The worst thing they could do at this stage is lock themselves up with some ham-fisted suitors just to get a couple of press releases out.