I always assumed this was a shift due to VCRs, DVDs, and then DVRs and streaming. Today media can assume everyone can watch anything as often as they want. Older media had to assume no one would ever watch it more than once, or be able to look up anything they missed. Old movies and TV shows are simple in the stories they tell, simpler in dialog, and shorter in length, so you can mostly catch everything the first time through.
I always assumed this was a shift due to VCRs, DVDs, and then DVRs and streaming. Today media can assume everyone can watch anything as often as they want. Older media had to assume no one would ever watch it more than once, or be able to look up anything they missed. Old movies and TV shows are simple in the stories they tell, simpler in dialog, and shorter in length, so you can mostly catch everything the first time through.