I don't know about civilizational collapse as such, but ibn Khaldun's analysis of the empires of nomadic dynasties could basically be summarized as the first generation conquering because of their tight social kinship and powerful military culture of the steppe, followed by successive generations that lose both their bonds of tribe as well as the military power that gives the tribe strength. This occurs as the tribe and its leaders enjoy the benefits of leading a large settled empire (wealth, concubines, feasts, etc.) They are then supplanted by newer, more virile steppe peoples who start the process over again.

It's not a perfect social theory, but it's insightful analysis of the history of the region he was examining. As a short hand you could call this collapse by "laziness" or "decadence" or in his terms "loss of militaristic social cohesion" (which ibn Khaldun termed "Asabiyyah").

This played out in the constant succession in the Middle East of dynasties and groups that followed this model: The Ummayad Arabs by the Persian dominated Abbasid armies, the Abbasids by the Samanids, the Samanids by the Buyids, the Buyids by the Seljuks, the Seljuks by the Mongols, the Mongols by the Ottomans, the Mameluke and the Safavids and so on until the last great steppe conqueror Tamerlane and the succesor Timurid kingdoms.