Desilu Studios took the old RKO film studios (the studio that made King Kong) and did a big makeover. The result was great sets sometimes. Twilight Zone was mostly made at the then old rotting MGM studios. Check the ep 'Stopover in a quiet town' and you can see the studio backlot rotting. It was like the difference between a well-kept preppy boarding school and a low budget ghetto high school. Some of the reason anyway. See my other postings on TZ.