I'm surprised they don't sell doughnuts
The profit margin is much better than popcorn
( Maximinimus you stick around I'll make it worth your while, Tue 16 Jun 2009, 12:36, archived)

IIRC, popcorn has the highest profit margin of pretty much every product ever.
Cinemas sell it at something like a 300% markup.
( Noit happy baby orangutan, Tue 16 Jun 2009, 12:45, archived)