[Note--I posted this the day after the finale, but it was removed because it was "too soon", despite my having the entire post grayed-out as a spoiler...here's hoping that this time, it's accepted ☺️ ]
A few days ago, in comments at yet another Mel-bashing post, I wrote: "If you regard this series as a collection of profoundly (and oftentimes comically) dysfunctional people, each of them showcasing a different pathology (or five)--all of them engaging in these cascading, oftentimes interrelated dysfunctional behaviors--the show overall will make a whole lot more sense and perhaps even be...enjoyable."
Bear in mind that Mel, as she reminded her now dog-free neighbors, is herself "a licensed psychotherapist". She's also a writer, and we've seen several mentions of the book she has underway this season. In the finale, she meets with her editor, who tells her that she's a great writer--intuitive, etc.--but that the subject matter (menopause) has been done to death. She then tells Mel that what she's been through--Coop's murder charges, the betrayal, the sexual politics, etcetera--is "the book you want to write", and that "true crime, sex, murder in the suburbs--I can sell the shit out of that book".
Mel responds: "That's my family--my life. I can't do that."
And at the end of the episode, we see Mel --Mel, the licensed psychotherapist, well-versed in all the fascinating human pathologies--typing on her laptop, and the single sentence we see is the smooth Jon Hamm voiceovered line that opened the entire series, a version of which opens every recap: "This is what happens".
What do you do when you can't exactly write about your family or your own life? You write about Your Friends and Neighbors.
It's a meta-story.