Makes totally sense. But not every movie is shot in artificial lights (tv ads, documentary films etc)
Most of these scenes also either don't have 15 stops of DR worth of details that need to be captured (most daytime scenes) or take place in dark environments where you need to increase gain and are limited by that rather than by baseline DR anyway.
Video is unlike stills. The focus is on the action and on the foreground elements, not on what is happening in the background. Then there are the added elements of dynamics and sound. In a still photo, the details have to say everything. In video, half the screen area can be black, with light only on the actors' faces and a hint of detail in the background, with the sound of slow, dripping water signifying that they're in a dark drain or sewer, and we still know what's going on.
And panning, establishing shots of nonmoving subjects (e.g. the shot of the landscape the scene is taking place in, before cutting to the actors) is often taken using a high-resolution stills camera, not a video camera.