How well could your boss do your job?

One of my coworkers told me about his wife.  She is in the first job that she's ever had where her boss doesn't know how to do the work that she does.  It makes her really mad.

My coworker and I were amused, because as computer programmers, that's just the way the industry works.  Nothing against my boss, of course.  His skillset are management-oriented, and completely unrelated to my technical job.