I don't think they're confused about episodic vs. serialized shows; they're talking about the plot structure of serialized shows often having a change of direction at every season boundary instead of resolution of the existing plot threads. That sort of meandering never-concluding plot can be annoying. One way to avoid that pitfall is by staying episodic, (Old Trek,) another is to wrap up each season and start from a relatively blank slate on the next, as if the seasons are episodes. (The Wire.) I think a third is to have all the story structure written in advance, as with a book adaptation, so there is a real through-line.

Yes I shouldn't have used the word episodic. The problem with your third solution is that it seems to be difficult to do with the current way TV series are financed and produced: You can't commit to multiple seasons at the outset and you also want to have an arbitrary number of episodes depending on how well the show is doing (milk more episodes if the show is doing well). There is also incentive to create cliffhangers so that subsequent seasons can be produced.

There are lots of mini-series which do book adaptations but it's hard to come up with examples that span multiple seasons: "My Brilliant Friend" did it I think and maybe you could argue early "Game of Thrones" but the story was never finished in book form either so it couldn't be said to be telling a complete story.

I don;t think "The Wire" gets enough credit for creating a format that conformed to the constraints of TV production while still being able to tell stories that spanned many episodes. You could have ended the series at any season (had it been cancelled) and it wouldn't have felt incomplete and yet the final season did feel like it completed an even larger story arc.

I have to mention Babylon 5 here, I don't think anything is as complete in terms of a 5 year, 110 episode plot. Note; don't read up on the plot, it's actually self-destructive.

It's great, strong recommendation.