This is possible because he seems to draw his identity from the traditions and laws of Umofia.
Wright claims this is a phrase used in "this particular African society" to describe someone like a tragic hero, " who is most unlike his community but who, through his great strength and his ability to do more than it has ever asked of him, and set examples it does not require, belatedly becomes its representative"(Wright, 79). While he certainly fits the other qualifications of a "great man," Okonkwo only seems to be unlike the community at the end, once everyone has adapted and changed.
So how is Okonkwo related to the end of traditional Umofian society?
If the system was complete, then Okonkwo's stubborn, inflexible observation of the rules would not have led to his downfall.
Wright also claims that Okonkwo's death was inevitable because through his inflexibility he was the clog in the wheel of progress.