Yeah, if there are studies, it's the billionaires who have commissioned them, and solely to see where they can gauge fans.
And I think the movie theaters took the queue from the pro sports venues. As a kid I remember Metrodome concessions being on the pricey side, while movie theater popcorn and soda at the local college games were pretty cheap. Now those types of venues have more than embraced the pro-sports captive audience model.