It's also just cheap. Next time you watch Dark Knight, which supposedly is a good movie, notice there are no two people talking on the screen at the same time. So you have for instance two people talking to each other in the script, taking a walk. Camera shows face 1 talking. Cuts to face 2 talking. Cuts to two of them walking in silence. Cuts to face 1 talking. You might see the back of the head of face 1. Etc. They won't talk together in the same shot. So, technically, they never talked, but the two actors had two separate sessions, telling their lines in succession with no context. Think of this next time you watch Dark Knight, how cheap it looks, how little chemistry there is between actors. They are all talking into a void! I guess it is much, much more expensive to have 2 microphones and sound guys, and moreover, to have all those expensive stars in the same locations all the time. I can't watch such movies any longer. It's pulp. Most of them are this way now. Only solo-acting is left.