Why did Buck refuse to rise and lead the team? What did he have that his masters lacked?

Buck is exhausted and underfed. Buck watches apprehensively as they clumsily take down the camp, improperly rolling the tent, and loading up the sleigh unevenly. Buck does not respect his new owners (Charles, Hal, and Mercedes). Buck had inner and outer strength. The dogs respected Buck's fair but tough treatment. Buck worked hard and shoed great leadership skills. Their new owners were the opposite of Buck.