I think the popularity of Seinfeld is linked to the stories and characters we first came to know as kids watching Mickey Mouse.
Just look at the cast comparison:
— Jerry = Mickey. The center of it all and mostly straight man reacting to chaos around him.
— Elaine = Minnie. The female point-of-view.
— George = Donald. The curmudgeon. Bad things generally happen around him. A few small, glorious victories too.
— Kramer = Goofy. Tall. Aloof. Lots of good things happen around him. Few bumps along the way.
Who can tell me that doesn’t line up perfectly?
As Seinfeld viewers, we’ve seen the structure of these four friends when we were kids. It is comforting. We know what they’ll be like around each other.
The genius of Seinfeld was that they brought these relationships to contemporary times and made it for adults.
The Oscar™ award-winning screenwriter William Goldman said, “The key to all story endings is to give the audience what it wants, but not the way it expects.”
In cultural story terms, Seinfeld did just that.