No offense meant, but were you alive when Carter was President? Carter had so mis-managed this country that anyone the Republicans ran against him would have won. We are just lucky it was President Reagan.
The economy was in the toilet, he let the Iranians walk all over us. The one military action against Iran failed. He was a weak and ineffective President.
Reagan was already well known to most voters. He served as a governor of one of the largest state in the Union. He had support of the party and of the people. He was only "too far right" for those on the left, where everyone to the right of them is too far right.
Few outside of Vermont ever heard of Dean. He was the governor of a small state. And he is "too far left" for those on the left.
I no not thing your comparison holds water.