Theater managers fought to stop patrons bringing snacks to the street, but it was a losing battle. According to New York Times, a dealer, Julia Braden, was among the first to be allowed into the premises. In 1931, his business was earning him $14,400 a year, equivalent to more than $335,000 today, even in the midst of the Great Depression. In the mid-1930s, some movie theater managers began installing Pop corn machines in their theaters.

Smithsonian notes that, even when popcorn became mainstream, some theaters clung to the idea that concessions were low class. A movie chain installed popcorn machines in 80 theaters but refused to sell popcorn in its top locations. However, the profit gap between the two theater groups quickly made the chain realize it was wrong in its ways.

Popcorn’s popularity in movie theaters grew steadily during World War II, when sugar rations made other snacks, such as candy and soda, scarce. In 1945, movie theaters served more than half of the popcorn consumed in America.

According to New York Times, one of the first movie theater entrepreneurs advised, “Find a good place for the popcorn and build a movie theater around it.” That advice still rings true today. Some theaters derive up to 85% of their profits from concessions; Stanford Enterprise notes that the typical theater derives 40% of its profits from snacks.