With all due respect to Dr. Sowell, Dr. Carson's rise didn't occur due to, or in spite of, the color of his skin. It was due to a mother that believed in him, encouraged him and sacrificed for him. Today's mothers sacrifice their children on the alter of selfishness and self-absorption. Dr. Carson's mom sacrificed herself for her childern, not her children for herself.
America stopped being great when it's people stopped being willing to sacrifice for the greatness of others and instead sacrifice the future for a good time in the present.