1: the world is run by money.
2: because of 1, artists make works to make money.
3: people are just plain cheap and lazy
those aren't all the reasons, just the ones that spring to mind at the moment
blaming piracy for the lack of box office returns is just stupid in my opinion. It's stupid and it's a cop out of sorts. Make going to the movies something fun to look forward to if you want people to spend money at the theaters. I remember when I was a kid, going to the movies was something to look forward to. Also, I think the can think about having fewer screens than they have now. That might have something to do with it.