Also in Slate, Daniel Engber and Dana Stevens debate whether 3-D makes movies any better to watch.
But now we're back where we started. Critics of the first chart—the one showing percent of total gross revenue from 3-D—complained that the decline was merely the effect of having too few 3-D theaters. (Money was being left on the table, they said, because there weren't enough screens to go around.) Now we're trying to explain the decline in per-screen revenue by saying just the opposite—that there are too many 3-D theaters.
Either way, the prognosis for 3-D seems dire: There's either too much supply or not enough demand. For mainstream movies that can be viewed in either format, the added benefit of screening in three dimensions is trending toward zero.
Economists, media analysts, clever readers: I'm certain there's a much smarter way to evaluate this question, given the box-office numbers that are available. What is it? Please e-mail me your ideas or post them below in the comments. I'll follow up on your thoughts next week.