>>715175314 (OP)Because it was before the Californian "in-group" actors became the managers and before SAG entrenched them in safe positions that are guaranteed to land them work no matter how complacent they become.
It was made by recording professionals and ppl from the localization team back then getting the up and coming actors, and sitting in the recording studio with them telling them "Make it MORE SINSITER, YESS!"
Whereas now it's just a routine practice. Someone goes
"Faster." "Do it again. Slower." "Good." and then they all know each other in advance and hang out together in LA after work.