Folks should keep in mind that the prices are substantially set by the production houses, not by the theaters' indeed the bulk of the revenue from ticket sales go to the production houses. The theaters tend to make their money
on the concessions.
I doubt decreasing prices would improve anything for theaters. LoraJ alluded to the problem with folks, especially children, misbehaving, and that would perhaps be exacerbated by lowered prices (not to mention how becoming the cheap hang-out in town would tend to increase maintenance costs). I think we need to realize that standard movie houses are an artifact of the past. There are so many new (and arguably) better ways to view feature films, these days, that we can consider standard movie houses to be non-viable in the long-run.
However, as spima3 mentioned, overall revenues are up. I think more and more people prefer having the theater to themselves, viewing, as LoraJ alluded to, a more crowded theater as a theater more likely to have folks in it who will behave in a manner that ruins the experience for others. The production houses have their pulse on their revenues, and know that sometimes high prices and low volume yield more overall revenue that low prices and high volume -- the Macy's versus
Walmart scenario. There is a place for both market sectors, but increasingly the low priced distribution mechanism for feature films is television.
IMAX is really the future; though some people don't like it, it does provide a viewing experience that you really cannot get from a regular movie house, and a viewing experience that home viewing really cannot compete with on any level.
However, home viewing is really becoming many people's favorite means of viewing feature films. OctMtnWoods mentioned subtitles as one reason. My wife is hearing impaired, so that's a big deal for us. (Though, to be fair, IMAX theaters tend to have excellent apparatus for viewing textual renditions of the dialog.)