>>17920856
Mansa Musa brought back only one known architect from his hajj and only a handful of other outsiders.
You're, like many people, simply ignoring the logistical nightmare that crossing the Saharan desert was in that era.
Very few people were ever doing a full crossing.
The "trade routes" mainly consisted in rare and occasional caravans forming a "chain", with each going from a specific point to another point, trading the merchandise and turning back. Goods crossed the whole desert, but people did not.
Mansa Musa's hajj was an exceptional event, a once in a lifetime thing (he never did it again btw).
Also, by the time Mansa Musa showed up in Egypt, no one had ever heard of Mali before almost all the infos in arab sources about Mali came solely from Al-Umari's retelling of the testimonies of Egyptians who had met some Malian pilgrims during Mansa Musa's hajj)..
Very few at the time would have been willing to go with him and attempt the dangerous crossing of the Sahara to reach some utterly unknown distant Wakanda they knew literally nothing about.