"Islam" is not a civilisation, it's a religion. Although the concept of the Ummah provides a sense of unity among Muslims, in no way are they a single, monolithic entity. The Mughals, the Ottomans, the Persians, the Umayyads, the Mamelukes, the Eyubis (Moors); these were all different civilisations that rose and fell throughout history, that happened to all be Muslim. In the 20th century, the biggest remaining Muslim empire, the Ottomans, collapsed and in their place many different nations were born. This doesn't show the collapse of Islam-one could make the same comment about the British, French, Spanish, Portugese and Dutch empires crumbling and losing their colonies: did Christianity slip? No. The fact of the matter is that in our modern day religion has a much lesser role in politics than it had previously, and nations that hold onto more theocratic structures tend to be viewed as "backwards" due to this. I understand, however, your reason for asking this question, but it's more of a complex question then how you phrase it. It should be more along the lines of: in the past, empires and kingdoms around the MENA region were some of the richest and most politically influential of their time. Now, however, the region is in turmoil, their states are unstable and as a result they are unable to economically and culturally keep up with the rest of the world. What has caused this shift in power? That question is a good deal more context-specific and accurate, and can be answered through research on colonialism, nation-states and nationalism, West-East blocs during and after the Cold War and the significance of oil to the global market, and how the presence of such a valuable resource affects domestic politics.