Persia is a text book case of this. Before Islam, it has one of the greatest civilizations in the world. After that, it was just another sandbox country.
Granted, it did progress into modernity for a season under the Shah and other rulers, but only because they practiced a softer modernized version of Islam.
Exactly. All of these countries (including Afghanistan, which was not really a state at the time, but was doing just fine on the Silk Road and was full of commerce and art and other good things) lasted just long enough for the dead hand of Islam to destroy them with its hatred of material creation and its fatalistic belief that its god is some hideous monster that hates humanity and is ready to destroy it at any moment.
For the conquered, the only solution was to abandon their own civilization and put themselves under the profoundly anti-human grip of sharia, which was “law” invented by Mohammed to subjugate peoples and consolidate his military conquests. This usually took about 2 generations, or perhaps 3 in a very resistant group, to fully kill a society.