The story of the Ugly Duckling doesn't teach kids to work hard and overcome adversity. It teaches them to sit on their ass and wait for genetics to kick in. The Duckling didn't really pay any dues. As soon as he became a beautiful swan it was just like suddenly inheriting a trust fund. There was no effort involved. He had to survive being ugly, but he didn't have to figure out how not to be.
You take some critter that stays ugly and still amounts to something, then you've got a story.