Why was the kingdom of mali more successful than gahna

The kingdom of mali is more successful than the kingdom of Ghana because of the Niger river which provides a more reliable economy to the kingdom of Mali. Mali was located in an area along the upper Niger Riverwhere agricultural activities flourished. Camels and donkeys remained a passe' and old which was still used by Ghana.

Well, one reason the mali empire is more successful than gahna because it was the largest, located in west africa and extremely influenced and developed. another reason and explanation is because the culture of the region through the spread of its language, laws and customs along lands---did i forget to mention? it's land was full of wealth.