Compare that to a film that doesn't excite me (or most of the general population), and all of a sudden I'd rather wait for the movie on Netflix or whatever, because then £16 is better spent on a takeaway and watching from home.
I know films are different strokes for different folks, but the cinema is really overpriced if you're in the 'shall we / shan't we' category, so I can understand people just thinking - I'll pirate it and save the money (or spend it on dinner) and watch from the comfort of my home - the risk to reward is so much lower.
I'm not saying that's right - just with the cost as it is you need a great (or mass appeal) product to get bums on seats. Or you have lower the cost in cinemas and make going to the cinema the experience ("we can choose a film when we get there") rather than people just going to see something in particular.
EDIT: Regardless, great article on TF ;-)