Think about what has changed in theaters over the last 50 years. The screens got wider, yes. But the changes in sound have been astronomical. We went from mono to stereo, Dolby Surround, Pro Logic, THX, Dolby Digital, DTS, 5.1, 6.1, 7.1 with one to four subwoofers.
While you're watching a movie you hear thunder off to the side, children in a playground, a flock of geese flying overhead, traffic behind you or wind swirling around. A high quality, properly designed and calibrated surround sound system transports you out of the room and draws you INTO the movie.
Most people don't even realize how important MUSIC is in a movie because the music is blended so well into the scenes. When there is no dialog between actors, there is music, setting the emotion, mood and pace of the movie. Next time you're watching a movie, notice the music and mute the sound when there is no dialog. The whole movie experience crumbles without the music. Theater speakers must be able to reproduce musical instruments accurately or they are not worth having. Great sound is more important than a big screen.