I suspect this has to do with Europe's water-dominated geography. Traveling between Ethiopia and Mali -- two of the largest sub-Saharan "countries" of antiquity -- requires taking a caravan through the desert and/or jungle. But going from England to Poland is a boat ride. So reestablishing communication between distant societies probably happened much faster in Europe, which supported knowledge-sharing and thus scientific progress.
That things did not completely fall apart when the plague hit may be due to having relatively strong institutions, but again I'd argue that what mattered here was at the parish level, not Rome.
Ethiopia was also quite a centralised state in medieval times (with a uniting church language playing a role like Latin's). But we don't actually know whether it suffered a larger or smaller plague at that time, it seems. We do know that it did not suffer collapse on the scale of pre-Colombian American civilisations, that we would certainly know about already.
Some parts even non-Christian.