Film and TV serials are two completely different mediums
Different, yes. But not as different as your example of a painting vs a TV series.
The modern scripted series IS the evolution of and replacement for the obsolete, way-too-short traditional movie. My analogy of the troubadour being replaced by the printing press is simply correct. We were only saddled with pathetically short movies, because people had to physically go to the theater, and still have time to get home and cook dinner.
Those days are over, and good riddance to them. The paradigm has shifted. There is no longer any reason to fuck around with arbitrarily far-too-brief motion pictures. Of course, there will always be people who cannot let go of the past, and insist that the limitations of obsolete media are somehow features, rather than bugs. Lots of people still unironically insist that black-and-white photography is somehow better, more serious, more artsy.
That's just nonsense. The page has turned. Technology has moved forward. Longer IS objectively better than shorter. Color IS objectively better than black and white. More IS better than less. Every child knows all of this. We only begin to deny facts like these, when we grow old enough to become insecure, and in need of things to brag about, show how "sophisticated" we are, etc.
We don't have to accept the limitations of yesteryear, unless we insist on it, for reasons of hipsterism.