As a person who just built an (admittedly minor) AA, and tried to maintain it for a month and a half of continuous operation, I can say that the cost must be the problem. But for those who say that the wow factor is gone etc, that is like saying that live theater has lost it's wow. I think that live theater will always be better than movies, but again it is the expense and maintenance.
I think everything has pretty much lost it's wow factor. I hardly ever go see a movie anymore that is not in 3D. There is nothing we can do about the fact that extraordinary things continue to become more and more everyday as everyone increases the amount of time they spend experiencing modern entertainment.
I don't think that means they should give up though and focus only on thrill rides or VR rides. They just need to focus on the story just like the motion picture guys. The story and the immersion in an invironment makes a great attraction, and you should use a smattering of all technologies to tell it. Then people will want to see your attraction.