What factors led to the decline and eventual collapse of these muslim states? did they have any problems in common that would explain their fall?

 the main factors that led to the collapse of Islamic states were:
wars,
The Islamic states were involved in constant internal and external wars that continuously weakened them. most of the wars emanated from succession battles, which also led to political instability.

economical struggles,
Probably as a result of constant wars, the Islamic states begun to face economically as  a large amount of money was put into wars.