I don't know if it's an obsession with things that are of no importance to their daily lives. The #1 and #2 places we spend our time in this country are work and sleep which both have legitimate importance; everything else, family, food, entertainment, knowledge expansion, has to compete with those. We only have so many hours in our lives and in the end how much we knew about SCOTUS really doesn't matter, neither does our Disney movie knowledge of course, but it's generally more fun to learn about Disney movies than to learn about SCOTUS. Maybe we should hire some Disney marketers to work on expanding knowledge of the government, nothing helps people know names and titles like plushy dolls.
Yes, no individual judge has been on SCOTUS as long as Snow White and the Seven Dwarfs has been around.