That episode of Seinfeld stuck with me for a long time - and not in a good way. It really was the capstone on a series that celebrated apathy, indifference, and casual cruelty. I wrote a post about this shift in our culture about a year ago, when I realized how media had gone from celebrating togetherness, relationships, and family values to the sort of bleak violence that seems to be the default today. At the beginning of the shift we had Friends, which had some positive emotion in it, and ended with a wedding, and at the end we had Seinfeld, which, as you pointed out, ended with a prison sentence.
Today, if you want to experience anything like family you have to play a violent video game like The Last of Us, which celebrates the last vestiges of trust and togetherness in a post-apocalyptic wasteland, or the new God of War, which looks to be a button-mashing slaughter-fest but at least explores the relationship between father and his son, who are going through this rampage to honor the last wishes of a late wife/mother.
But hoo-boy, my hat's off to anyone who's trying to raise a close and loving family these days. It's can't be easy with this media landscape.
Yeah, destruction of the family unit is popular int he post-modern, subjectivist, relativistic, solipsistic world we are conditioned into now...