Whenever I hear someone talk about the "Golden Age of Television," what they're really doing is stroking themselves for watching a bunch of super-depressing stuff that makes them feel sophisticated.
IMO, one of the reasons it's called the Golden Age of TV is not just because the shows since the late 90's have been overall better than what came before, it's also because of lack of quality in what came before.
What passed as "drama" in so many 60's and 70's shows was one dimensional stories populated by one dimensional characters. There was no subtlety, they seemed to feel the need to make sure everyone in the audience receied a step by step tutorial so that they knew who done it before the last commercial. The detective show were the worst. Almost nothing that happened was unexpected or controversial.
My mother used to love these shows. She would complain bitterly is the story didn't conclude in one hour. Yeah, she hated the two-parters. The shows had little depth or complexity, likely because the networks saw those things as ratings killers. It's like they knew my mom personally.
There were some exceptions of course, Playhouse 90, Twilight Zone, Alfred Hitchcock Presents etc, but for the most part, the networks kept it simple and boring.
I'm also really annoyed with just how heavily serialized TV has become. I'm all on board with an ongoing plotline that rewards the attention of longtime viewers. But at the same time, I think it's important for there to be some kind of reward for just sitting through a single episode.
I think any competently written one hour screenplay is going to have a beginning, middle, and a discernible end. The end may not be the end of the overarching story, but simply the end of a single episode.
What I think happens is that because we know a show is serialized and there is an ongoing overarching story, we tend to overlook what is an actual end to the episode at hand. A lot of times an individual episode's ending in a serialized show is subtle, but if you look closely enough, it's there. The endings to stand alone episodes are easier to see sometimes because we know there is no more story.