This is actually rather a tragic realisation in the novel. Kumalo, having never left his tribe and the land of his tribe before, experiences an incredibly bewildering and shocking reality as he journeys to Johannesburg, but at the same time he learns some valuable lessons about the realities that are facing so many of his people in South Africa, concerning the temptations they face and the harshness of life for those that have moved to the city. However, it is in Chapter Thirteen, when he accompanies Msimangu to Ezenzeleni, that he is able to think about what he has seen, heard and experienced, and is able to think about going back to Ndotsheni and how he will incorporate this knowledge. He begins to get excited as he thinks about plans and rebuilding the tribe, yet at the end of his dreams, we are told that he is "caught up in a vision, as a man so often is when he sits in a place of ashes and destruction." This leads to a crushing epiphany for Kumalo:
Yes--it was true, then. He had admitted it to himself. The tribe was broken, and would be mended no more. He bowed his head. It was as though a man borne upward into the air felt suddenly that the wings of miracle dropped away from him, so that he looked down upon the earth, sick with fear and apprehension.
Change has happend so fast and so quickly, that the realities of urbanisation, racism, fear and poverty mean that Kumalo's beloved tribe is now broken without any hope of repair. This is what he admits to himself.