Okafor actually had the innate conditions too, but he learned Duncan's style of leadership, leading his teammates through practical actions. However, he lacked Duncan's ability. Apart from providing his teammates with relative emotional stability and calmness, his leadership skills were significantly inferior to Duncan's.
Gerald Wallace actually had the best qualities to be a leader. He had risen from the edge of the league to become a top defender and an All-Star, possessing the heart of a leader but lacking the mind of one. Take the incident where Millsap 'betrayed' him; they played together for most of the season, yet Millsap only learned the aggression, skills, and basketball awareness by figuring it out on his own...
Aside from his age, another reason Zhang Yang was reluctant to proactively discuss these matters was laziness.