A most objective book on the subject I have read to date. The summation is simple: the timeliness of adopting and advancing of the right propagators for legitimacy to be in power. Those that failed to do so( such as the Ottoman and Spanish Empire) regressed, while those who did such as the Danes and Northern Europe( England etc) excelled in all fields to create successful nations.
Neither Christianity nor Islam as religions are the reasons of failure or success. Greed to remain in power and the exclusion of the "other" is at the heart of failing nations and empires. Inclusion strengthens nations building while exclusion and extractive practices weaken and destroy those that practice it.
Till the Middle East evolves to have inclusive systems of governance, it will remain backwards and in turmoil.