If you knew anything about how the technology works, you would know that closed captioning at theaters is a matter of installing a LED projector at the back of the theater and providing the viewers with a plexiglass reflector that they stick into their cup holder. It is not a question of retrofitting every seat. The tech is dirt cheap.
And even as cheap as it is, in the greater metro Seattle area, there are only 4 theaters that have it. And not 4 theater complexes. Literally 4 theaters. For example, the 11-screen complex in Pacific Place has a single theater equipped with it. And most the time, the complex choses not to present movies with captions in that particular theater, and pretty much never does so on weekends. If the theaters equipped more movies with the captioning devices, I would go to the movies more often. But the fact is that the market power of deaf and hard of hearing people isn't big enough to warrant it.
Mandating companies to take reasonable measures to accommodate the needs of disabled patrons when the market can't is part of belonging to a civilized society.