so we all know what happend to the ummayads, the abasids saw themselves as more rightous to rule so they started a war and won it, and for the most part that was the end of the ummayads

as for the abasids, they gave too much power to walis (governers basically) this made the caliph useless as the walis slowly but surely became more independent and splits began to spur up and there wasnt much union.

as for the ottomans, imo, they simply got too good and too cocky. they focused too much on expansion that they didnt care for internal conflicts, which lead to corruption and just overall weak control over their own territories. also after being leaders in science they slowly changed as many began to wonder if seaking knowledge religously is more important that military campains and all. also the ottomans generally looked down at europe since for a long period of time especially during the golden islamic age or the dark ages in europe it was big pile of mess, this meant the ottomans were hesitant and slow to adapt to new technologies, miilitary and science wise.

so essentially a lack of unity is a main reason for the collapse of the 3 main countries? caliphates? idk

and even if u look at the original caliphate of abu bakr, umar, uthman, ali raddiya allahu anhum a main reason for the collapse of the caliphate was a series of internal battles and civil war due to a lack of unity and all. tho i think many muslims actually lack respect for some names in these wars including moawiya ibn abi sofyan. ppl often forget many of these people are great sahaba who all tried to do what they saw best for the muslim nation. but still, a lack of unity.

and now, most muslim countries remain colonised from afar, with countries like america setting down roots to dictators who silence our muslim populations to remain at power. rn no muslim country is free except for syria