That’s because old movies were mixed stereo or mono, not surround, and your TV can naturally handle stereo or mono.

The problem most people in this thread are having is a result of their TV crappily downmixing a surround signal to a stereo signal. You have to set your streaming device to request the stereo stream from your streaming service if you don’t have a full-on home theater. Devices by default request the surround stream.

Any time this comes up in conversation at someone’s house, I set their device to request the stereo stream, and it’s fixed. Every time.