Hearing my daughter play the theme from Gilligan's Island over and over again as she practices piano has led me to consider the hapless castaways. They seem to be a metaphor for the mess we are in. As you can see, others have had this thought too. I even saw an author interviewed on his book on the subject. But I doubt that each islander represents one of the seven deadly sins. Maybe the castaways were actually dead and in hell. No, No, that can't be right, no TV show would do that! Nor do I think Sherwood Schwartz's explanation that the show is a metaphor for international relations is valid, if he really said this. (It is dumb enough to be true.)
But the analogies are so obvious they could not have been intended. 
First there is the millionaire, and his wife. They never actually seem to do anything, and he seems to always have an alcoholic drink with a straw. Everyone seems to have brought along a lot of possessions for a three hour tour—the Howes especially. The wealthy actually do a lot more than is realized, but often stereotypes have some basis in reality. The Howes are always ready to provide advice as long as no work is involved. What is weird is that every other castaway gives then deference even though on the island there is no reason for it.
The professor represents old-fashioned American ingenuity. He will get them off the island! But the Skipper and Gilligan seem to always mess everything up.
This is natural as the Skipper and Gilligan are the authority figures, the government, on the island. The government always messes everything up.
My blogging predecessor suggested that Ginger represents the propaganda machine. Maybe. In any event I always picture her meeting up in the jungle with the professor.
This leaves the unfortunate Mary Ann. Neither she nor the professor were important enough to be mentioned in the first season's theme song. She represents the common person who does all the work. While it seemed that Ginger helped, Mary Ann seemed to do most of the cooking.
Poor Mary Ann!Romantically Mary Ann's choices were limited—the Skipper or Gilligan. Not the best of choices. That's right, Mary Ann's only options, just like the common man she represents, was to be screwed by the government.
As for our heroes in real life, they got no residuals for their work. In real life they got screwed too.