Somehow, I am not surprised. And I would say that this is a kind of a "mechanism", which is true of almost any goods or services.
Say, a new brand of beer or smartphone is launched. These new products, enter the market and they are of a good quality, appealing, made with care. They gain following amongst fans, customers and the like.
However, as time passes, someone who launched the product in the first place says:
A: Hey, people got used to what we are selling. Let's cut down on the costs and reduce quality of our beer / tea / cars. They are so used to our product that they won't even notice the change!
B: Good idea. But what if they do?
A: Naaah. They still won't bother spending time to find a substitute.
And this is it. Maybe the same is happening either to your IMAX theater or to the Avengers franchise. They reckoned that these things got popular and, as money flows in, nobody cares about the quality and reliability anymore?