Mara Watts proved you didn't have to be physically strong to win the Hunger Games. Isaac Frey proved you didn't need book-smarts to win, either.
They won because they were strong and smart in their own ways.
Mara didn't have brute strength, but she was a great, nimble climber. Isaac never did well in school, but he was very street-smart and self-aware.
But District Five didn't support those qualities. They needed physically strong and incredibly brainy people to work and maintain the factories. It wasn't an easy job, after all.
But the two Victors still succeeded, in their own ways.