The one thing I have learned from history is that nothing is inevitable. During the crusades, the Christians ultimately were defeated. That being said, the Islamic forces almost bit the dust in 1254 during the French invasion of Egypt, followed by the sacking of Baghdad in 1258 by the mongols. In 1260 however, an outnumbered Mameluke army crushed a combined Mongol/Christian army at Ain Jalut in modern day Israel. That cemented a 300 year Caliphate out of Cairo until some upstart Portuguese bankrupted the whole operation. It’s anybody’s guess how this next crisis is going to play out.