I think all the options there ignore the _very_ _very_ obvious fact that popcorn is _not_ a competitive market, because most of the consumers in the market don't know the prices! If you disagree, try to recite for me how much popcorn costs at your nearest three major theaters right now. Do you check before you decide where to go for a movie?
This is well in line with my own pet theory of the free market, which says that people's brains can handle optimizing on one or _maybe_ two things when making a product decision, and anything else is overwhelming. For a theater, that's what movie you want to see, and what price you have to pay. Anything beyond that and you have to start making spreadsheets, and it's not worth it to anybody. So beyond the price and the main desirable quality of the product, producers aren't really forced to compete, because nobody will call them on it.
It sounds like you'd enjoy looking into "the paradox of choice" (the econ literature, not the junk science book with that title). There is a good bit of evidence that too many choices reduces utility and induces irrational behavior
This is well in line with my own pet theory of the free market, which says that people's brains can handle optimizing on one or _maybe_ two things when making a product decision, and anything else is overwhelming. For a theater, that's what movie you want to see, and what price you have to pay. Anything beyond that and you have to start making spreadsheets, and it's not worth it to anybody. So beyond the price and the main desirable quality of the product, producers aren't really forced to compete, because nobody will call them on it.