This right here, West Africa's current political economy has the worst of both worlds when it comes to country size and integration. Europe's smaller states (Slovenia, Montenegro, Baltic States) are economically successful in a wider international environment of regional integration and lack of borders, trade restrictions, or migration barriers. If there was still an interwar-era mess of tariffs, quotas, and migration restrictions, then the map of Europe would be made up of a smaller number of larger countries, and places like Kosovo or Slovenia would just be autonomous regions of a larger state.
West Africa's political map is a bunch of smaller nations like Central and Eastern Europe, but there's no EU/Schengen deep economic integration between them.