1. Many movies have great trailers and then the movie is crap.
2. To go to the movies is expensive specially when dealing with #1.
3. When you sit you realize you have this fauna of people making noises, talking
4. Besides the ticket you have to pay parking lot (depending on where you live)
5. You depends on a schedule and to get your favorite spot you have to wait late at night and leave the theaters after midnight.
6. Concession stands are super slow, super expensive!
I think its a combination of technology, and cost. My mother when she was a kid would go and spend an entire day at the movies for a nickel back in the 50s. When I was a kid it was a couple of dollars. Now its going upwards of 10 to 20 dollars per person.
Why spend over a hundred of dollars for a family of 4 which does not even include dinner, when we can easily stream decent movies for a tenth of that price.
So imo, we have a confluence of high price, poor experiences (as noted in the quote, loud people), and technology that offers a better less expensive alternative.
The other factor is the lack of truly gripping movies, at least for me. I'm not willing to spend a lot of money for the stuff that is being advertised. I'm willing to wait a couple of months and rent it from itunes, or see it on netflix. There are a handful of movies I'm willing to pay for, but those are now the exception and not the rule.