Could Christian Nubia survive?

Jul 2017
Czech Republic
I've recently read a lot about Christian medieval state of Nubia (present-day Sudan) - Makuria, Alodia and Nobadia. They created original christian civilization, merging Byzantine, Coptic, Arabic and local Nubian elements.
Christian states of Nubia collapsed in the course of XIV-XV century.
Causes of decline of Christian Nubia is still debated, however it's generally accepted, that immigrations of nomadic tribe and Egypt attacks were major factors.

Was - in your opinion - collapse of Christian Nubia inevitable? What rulers of Makuria and Alodia could do to prevent destruction of their realms? If Makuria and Alodia survived, how would their history look like?

Good analogy seems to be Ethiopia. Ethiopia was also Christian and experienced the same difficulties - incursions of hostile muslim neighbors, invasion of nomadic Oromo in XVI century, internal conflicts. However, Ethiopia survived, Makuria and Alodia didn't not. Why? I think that important difference was geography. Nubia was located in plain and had no natural obstacles against enemies, meanwhile Ethopia lies on mountainous highland, divided by many deep dungeons, sharp slops and inaccessible peaks. During rainy season, when dungeons were filled with water, travel from one area to another is often impossible. To sum up, Ethiopia benefited from geographical factors, Nubia not.
May 2015
Could Christian Nubia survive?
Of course it could, in one way or another. However, It would have needed multiple essential requirements:

1) Don't mess with the Mamluks. In the second half of the 13th century, they were one of the most potent forces of its time, smashing Mongols, crusaders, Armenians and what not. For whatever reason king David decided to provoke them in 1275, when he attacked Aidhab, one of the most important towns on the African Hajj route. In the aftermath the Nubians got their ass beaten and became de facto puppets. More clever alternative: Don't provoke the Mamluks, keep your heads down and continue the Baqt.

2) Stop the infighting. The 13th and 14th century was full of civil wars ravaging the country. The one in 1365 ultimately resulted in the loss of huge chunks of territory, including Dongola.

3) Increase the contacts with Christian Abyssinia. We know only little about the Nubian-Abyssinian relations, but it seems that they were always rather limited. Intense relations with Abyssinia might have resulted in a strengthening of the Christian faith and possibly even military help (especially since the early 14th century, when Amda Seyon made his empire the strongest in the Horn). Via Abyssinia Nubia also could have requested Portguese help, resulting in fresh cultural impulses, and, more importantly, guns.

If all these conditions would have been met then, i think, the chances for a survival of the Christian-Nubian civilization would have been much higher. Nevertheless, there are still problems which aren't that easy to solve: How could the Nubians prevent the Arab take-over, especially in southern Nubia? How could they avoid the plague depopulating the Nile Valley? What to do against the shift of trade routes? What about the African raiders from the south?