What's missing in the gospel we spread?

North American churches have been sending missionaries to Africa for over 100 years. When I was in South Africa, there were churches everywhere, the effect of missionary effort visible every Sunday morning. Yet with all this apparently successful evangelism, why does the continent struggle so hard to enter the first world?

It begs the question: why hasn't Christianity made more societal impact? We witness extreme poverty, disease, crime and war in many areas of the African continent. Culturally speaking, the Gospel seems powerless there.

Then one day I heard a sermon preached by our dear missionary friend. He asked this rhetorical question to the group of church leaders he was preaching to: "If you had a choice to choose between being a pastor/missionary or the president of South Africa, what would you choose? Of course you should choose to be a pastor because it is much more important to represent God than a country!"

It seems self-evident that one way of rendering Christianity weak is by demeaning believers that fill functional roles in society--as if believers can't reflect God's lordship within those roles. Doesn't the good news of the kingdom of God have anything to do with the way believers live their lives within the kingdoms of men?