Unconscionable Movie Popcorn Price Gouging?

Slate.com has an interesting article on the history of movie theater concession stands, which are the lifeblood of the theater business - they account for 40% of theaters' net revenue!

But it wasn't always that way. Far from embracing food sales, many theaters were downright hostile toward them up until the 1930s. "Movie theater owners wanted their venues to remain upscale, free from the chomping of snacks you'd find at burlesque shows; and they wanted their plush theaters garbage-free."

That all changed during The Great Depression, when theater owners sought new sources of revenue, and started selling popcorn for 10 cents a bag. And they kept raising the price over time, way above the rate of inflation.

Assuming movie popcorn today costs about $4 per bag, that is a 40X increase in price. Compare that to gasoline, which sold for about 20 cents a gallon in the 1930s, and now costs about $3, a mere 15X increase in price since the 1930s (see chart above, click to enlarge).

Just wondering, what's next? A "Federal Price Gouging Act" for movie popcorn?