There's a whole world of people for whom the bargain side of everything matters more than the thing they got a bargain on.
My dad is like this -- he will always put up with inferior quality or drastically reduced choice if it saves him a buck and it really has nothing to do with his financial status. In fact, he often has broken or otherwise unusable things cluttering his life that he can't use but can't get rid of because he "spent good money on them"
Meanwhile, he spends so much time shopping for a low price that he doesn't have much time left to enjoy the thing he was looking for a bargain on or the experience is so degraded by low quality that he doesn't get any enjoyment out of it.
In terms of this, it's ridiculously expensive for an average at-home movie night. There's a million movie choices for $5 or less at home.
But there's a lot of ways I could see $30 being reasonable -- a big new movie for a group, people with kids who'd spend $30 on a babysitter alone, etc. It kind of doesn't have to be the greatest movie ever made, because it's about the larger experience. Sure, you could do it 6 months later when it hits Redbox, but by then the impetus is gone because it's just another title.