Cinemas tend to not show classic movies unless there's a special reason (like a rerelease) or they're independent theaters. In my city we have a 12-screen commercial Cinemark theater, which only shows whatever movies will make the most money, but we also have a one-screen theater that shows everything else, including obscure/independent/foreign films, classic films, and cult films. But they're only shown half the week, a few showings per day. I just checked the website. The Princess Bride is going to be playing next month. *tempted*
The sucky thing is, apparently cinemas make very little money from ticket sales, most of it goes to the production company, etc. They instead get their profits from refreshments, hence the huge markup. As for the actual ticket sales, per screening they don't even make any money unless there's a certain amount of tickets sold (at least 20 or something), which must suck, because it seems like whenever you go see a movie on a weekday, there's only like five people in there.