A few thoughts.

Today, it is fashionable to treat organisations as franchisees of Al Qaeda. I don't think that's the only way to look at Islamist terrorism in Africa.

I think Al Qaeda made the idea of violent jihad more attractive. The Kanuri members of Boko Haram don't have to look up to Osama Bin Ladin as an example of a jihadi - they have Muhammad Al-Kanemi (1776–1837). Similarly, the Hausa/Fulani jihadis have Usmanu Dan Fodio (1754 - 1817).

There's a lot of history to ponder over - Osama just showed them "it could be done", but many young men aspire to be the next Dan Fodio or Al-Kanemi.