Tbh this question is a bit like asking what caused the fall of Rome. There are so many factors in play it’s tough to point to one and say definitively THAT was the thing that caused it to happen. The decline of science was largely the same as the decline of the Roman Empire. The Arabic world simply became much more fractured politically and religion came to play a much larger role in dictating the organization of society.

The anti-science movement could be compared to the inquisition who hunted down science in the Middle Ages.

Religion and science very rarely work well together and even when they do, the science often becomes the religion which endangers the scientific method and puts you back at square one.

‘it can be traced back to the rise of the anti-philosophical Ash’arism school among Sunni Muslims, who comprise the vast majority of the Muslim world.’

There are a number of caveats to that, but I’d suggest checking this out.

I assume when you say ‘in modern times, the mainstream view is quite different.’

You are referencing the current state of Islamic science?

In that case it is largely to do with the sudden rise of Wahhabism and the fact that it is a state sponsored religion for Sunni Muslims in Saudi Arabia, which is literally the Mecca of the Islamic world.