It's even less "diverse" than Tom Sowell indicates. There are several hundred law schools in the United States, yet every one of the nine SCOTUS justices went to law school at either Harvard or Yale!
Time was when geographical diversity was a factor in choosing SCOTUS justices. No more. In fact, an amazing four of the nine grew up within New York City.
That’s the only place besides Hollywood where there are any smart people. Everyone else lives in Flyoverland./sarc