What is your opinion on Mona Hossein's book 'Longing for the Lost Caliphate'?

I have been reading Mona Hossein's book, 'Longing for the Lost Caliphate'. The book meticulously covers the aftermath of the defeat of Baghdad in the hands of the Mongols, depicting how decisive the Ulamaa responded. Many years after it, Ulamaa like As-Suyuti wrote on it, mourning and lamenting the three years spent without a Khalifah for the Muslim Ummah. Even before this incident, Imam Ghazali warned of the dangers of living without Khilafah.   The book then goes on to cover the abolishment of the Khilafah in 1924, illustrating how fickle the response was compared to the response after the event of Baghdad. It was nothing more than the intellectual regression that ensued as years of negligence of the Shariah was going on under the Uthmani Khilafah.   This is what becomes clear 80 percent through it:  That unlike the time of Baghdad when the illiterate Mongolians came to burn and conquer, the enemies of Islam were driven by their ideology at the time of the Uthmanis.  Due to intellectual and ideological decline, the Ummah and its Ulamaa could not make sense of what happened after World War I, so they couldn't react decisively. This was in addition to the western agents in operation that established foreign influence. When one looks at it closely, the Khilafah was ripe for downfall because of how steppe and deep the enemies were into the khilafah with its officials like Mustapha Kamal and many of the Pashas...   At the event of Baghdad, the Ulamaa were not influenced by any external or alien thought, despite being aware of them. So they only went with the Islamic position that having a Khalifah is more important than any other obligation. Whereas the some of the Ulamaa at the time of 1924 were influenced by western thoughts. Hence, they provided fickle and weak decisions - this is not withstanding the fact that there were strong personalities that spoke for the khilafah.   Hence, the importance of intellectual dawah cannot be overstated. The Ummah will attain full revival after the re-establishment of the Khilafah - political, economic, spiritual, educational, and social.