The Storyteller
The oldest invention in serial drama was to stop a story before it ends.
In the frame story of the One Thousand and One Nights, a king takes a new wife each night and has her killed the next morning. Shahrazad volunteers, tells a story through the night, and breaks off mid-tale at daybreak. The king, wanting to hear the rest, puts the execution off by a day. It went on for a thousand nights and one.
Inside that story, then, to tell is simply to live. Before the cliffhanger was a technique for building tension, it was a lifeline. When television leaves a question hanging at the end of the week, the shape of what it is doing is probably the same.