I heartily agree The Duke was a good actor. But audiences liked his strong personality. They just liked John Wayne.
People love strong male characters. They relate to and admire them far more than they do “sensitive” male characters.
During his heyday, John Wayne played a critical role in providing Americans with a sense of national pride and patriotism during a time of war. He embodied the courage, liberty, and moral principles which were/are uniquely American.