Its over because Mario Puzo ended it perfectly in the novel. Yeah, sure, Part II's ending added some nice touches but there's nothing more worth telling now (and Coppola sure ain't the one to finish anything).

I've never been able to understand why some feel the need to have everything wrapped up neatly in a little bundle and told in the smallest detail to the nth degree. Like "Sopranos" fans who NEED to know what happened to the Russian in the woods or wonder if Tony will ever get Melfi's rapist, this DOESN'T have to be drawn out anymore.