Realistically, how long could the Emirate of Sicily have lasted?

[The Undead Martyr]

The Emirate of Sicily ruled the island for about two centuries, eventually falling apart due to Italian naval supremacy, Norman adventurism, and political fragmentation. But was it truly doomed to fall apart?

Sicily itself was not the only Muslim presence in Italy, but it was the most entrenched. Yet I suspect that the island's wealth made it an inevitable target, so I suspect that a more permanent presence on the mainland might be necessary.

 

[Ogrelord420]

The latest I could see is the 15th century but that would require it to be an Italian/Norman vassal (similar to Granada). Roger I's initial invasion was largely supported by local Arab rulers, so it wouldn't have been impossible for him to have just been enthroned as a vassal. It would then require the Emirate to not go against Hohenstaufen ascension, which IOTL got the Arab Muslim population deported. Then they'd end up like Granada, being annexed by the Spaniards and either deported or forced to convert.

 

[HyperMuscularDemon]

How about the earlier Muslim invasions around 700 succeed? Also, have the Norman kingdom of Sicily survive for much longer and tolerate the Muslims for much longer. That way, there can be a bigger Muslim prescence in Sicily and the Norman Kingdom of Sicily could endure for much longer. Also, depending on if the Norman Kingdom of Sicily manages to expand onto North Africa, you could see North African Romance surviving and Italy join the Islamic trade routes to West Africa, the East African coast, and even Asia, which would benefit Italy and Europe to a extent very much.