I wouldn't want my mayor spending huge amounts of time trying to solve the n-queens problem in Java. Just like I wouldn't want the mayor ignoring other duties to write a critique of the collected works of Frederick Douglas. But I would want the mayor to at least have heard of Frederick Douglas, to be able to have an informed conversation on the matter. Same with Java.

iOS hasn't supplanted Unix - it's derived from Unix, and validates its good design. As impressive as these devices are, I'm glad I still can have my clunky old PC's where I can remove and add hardware and software as I like.