And this is exactly why they pulled out of the top AMC theaters. No surprise they're also the most expensive ones. The AMC at citywalk in LA is almost 20 a ticket for a basic 2d showing.
It's apparently not the ticket price that they care about. They removed support for the River East 21 in Chicago, which has 21 screens and shows a lot of foreign and limited releases. You could probably go there every couple of days and see a new movie you haven't seen before. Ticket prices there are actually cheaper than the 600 N. Michigan AMC which they still support. But that theater only has 9 screens and basically only shows blockbusters.
Likewise, the Webster Regal in Chicago is about $3 more per ticket than theater they dropped support for. But they don't carry all the limited/foreign releases that River East does.