Okay, well the success of what you term “Europe” was really influenced by Middle Eastern populations such as the Israelites, and the scholasticism in Oxford and the British empire (for example) was heavily contributed to by Christian learning and trans-Turkic trade with the Middle Eastern populations.
To begin with, you are wrong. Islam spread to West Africa at approximately the same time as it spread to North Africa, the 700’s. Islam is no more “authentic” to North Africa than it is to West Africa. Both pretty much got hit by branches of the same wave. What you are asserting is like saying that Japan is basically a rip off of Tibet because they both practice Buddhism.
In practical terms, North Africa’s influence on West Africa has been severely limited by that big huge desert that basically only the Tuaregs could cross- and the Tuaregs are not a particularly shining example of orthodox Arab-style Islam. They tend towards a synergistic semi-animist strain full of it’s own unique complexities. They were not telling anyone to build libraries.
While it is a diverse and cosmopolitan place with all kinds of influences, through the centuries, West Africa has developed it’s own Islamic culture and practice that is distinct from Arab culture. Nobody is ever going to go to Djenne and think they are in Casablanca. Islam has blended with local cultures to create something that is uniquely West African. The music, the clothing, the customs, the way of governing, the celebrations…they are all different. West Africa is it’s own thing, not some kind of fake-o Arab culture. While Islam was no doubt a positive influence on their ability to develop advanced empires, that doesn’t make anything any less African. It’s not like there was some kind of Arab overlord orchestrating the whole thing.
Anyway, West Africa- pretty much all of West Africa that was not impassible desert or malarial jungle- had a pretty darn fine imperial age. They had rich, learned empires that lasted for thousands of freaking years and still exist today. You can’t tell me that just being kind of near Arabs is enough to make an empire last for centuries. Why is it so hard to admit that they had some golden times?
Here is the Wikipedia page about Africa’s empires. Try reading it and learning something. African empires - Wikipedia