> 3D takes up time slots that could otherwise go to 2D showings, so it's zero-sum

3D is typically enhanced price, and serves as a way of extracting more money from the segment of the population willing to pay more to see movies in the theater. Without 3D pulling in that segment, the profit-maximizing 2D ticket price would probably be higher.

I doubt it. When 3D movies started to appear in the cinema, 2D prices did not go down. The 3D tickets were simply higher by, in Ireland, several euro, ostensibly to pay for the extra production costs.

When the 3D movies disappear, is it more reasonable to expect that cinemas will take the cut to their income, or try to raise their 2D ticket prices to make up for the lost extra revenue? I'd expect prices to go up, at least in the formerly-3D theatres that already have the upgraded, premium equipment. In fact, one of the ones nearby does sell tickets to their premium-level theatres for a few extra dollars, even for 2D shows.

Ticket prices generally increase over time. It's quite possible that 2D prices would.have increased faster without 3D, but obviously impossible to verify.

3D also usually monopolizes the best (tech) screens/sound systems.

I'd pay the 3D fee to get in the most modern 2D theatre experience possible. I also get frustrated that 2D showing times can be quite limited if I want to see it on a system better than what I have at home.

There's always an option to bring 2D glasses [1] to a 3D movie showing.

[1] Not a joke: on Amazon you can find polarized glasses that work with most theaters where both lenses are polarized to just a single camera (left 2D and right 2D). I've got a friend that experiences motion sickness at 3D showings that uses them to see movies where everyone else wants to see 3D. One of the lesser utilized but awesome tools with some of the home 3D TVs (like my LG) is to have one player with left 2D glasses and the other with right 2D glasses and play a "full screen" coop game.

My bet is that people just wouldn't be willing to pay as much for a 2D movie. If there were only 2D movies at 3D prices, people would just go to the theatre less. Which is why, whether consumers like it or not, theatres won't let 3D die: it's their profit margin, like "whales" are for casinos.

> "enhanced price"

That's a very friendly way to put it :)

Alternatively, higher prices for 3D could be offsetting the reduced revenue of the smaller viewership.