Yup, fewer screens. Even this weekend, it's on
fewer screens that Alvin or Sherlock Holmes. It also has a longer running time, leading to fewer showings per day.
As for people coming in and talking up ticket price inflation, that's a bogus argument. Ticket prices have gone up faster than inflation because the overall marketplace has been changing. Theaters are competing with the video and television markets, and rising prices are part of that competition, as theaters make up for lost ticket sales to the home movie formats.
So when people make the argument to adjust for ticket prices, or that Avatar is making so much because of 3D prices, they're actually saying we should pretend the movie was released into the same
marketplace as Gone with the Wind, in 1939. Would Gone With the Wind have stayed in theaters for years on end if there was a home video or TV market? And if that's the argument you want to make, you need to pull in all the post-theater revenue the movie makes from DVD/Blu-Ray, etc. in order to level the field.
But since we don't have that information on hand, there's no point making the ticket price adjustment to begin with. Adjusting for broader consumer price inflation is fair.