^Plus CRTs on film sets just didn't look good before HDTVs came along. Even when the monitors were synchronized to the film so they wouldn't flicker (a hard thing to do since they had different frame rates), the resolution was still poor. That's why most old TV shows and movies used mattes to simulate the screen image on a TV or monitor the characters were watching. They switched from film loops to CRTs in The Wrath of Khan
and it just looks so much more primitive. IIRC, it wasn't until Voyager
that they were able to incorporate real monitors into the bridge and other sets.