A big sale at Sotheby’s shows off the new potential and new collector interest in modernist African art. But while Western collectors drive up the money for those artists, “whole countries in Africa cannot boast of a single art museum of any renown. On other continents, you might expect to see at least one public art museum in any city big enough to have a sports team. But good luck trying to find a museum in Lagos, one of the world’s largest cities, that displays the work of a big-name Nigerian artist.”