Interesting history: in the original unaired pilot, the Professor was not an educator at all. He was a writer of travel books. "Professor" was simply a nickname he'd been given because he was well-read and had researched a great many subjects.
The Howell's were a well-to-do couple, but hardly the multi-millionaires they were later portrayed to be. Ginger was a secretary, and Mary Ann a store clerk. Gilligan himself was a Navy cook who was hired on the spot because the Skipper's real first mate was sick and couldn't make the trip. All of that changed, of course, when the pilot was scrapped and new actors were hired, retooling the characters into the ones we know today.