Some interesting thoughts and props to you for writing on such a topic.

I would add another factor- geography. Most of the Muslim world, with the big exception of the most populous Muslim country of Indonesia, lies in a fairly arid zone. Those Arab monarchies with wealth are also a geographical accident of oil reserves. Reserves discovered by and tapped with Western know how, to feed Western markets.

We can see a large population explosion in these arid climes over the last century, on land with limited cultivation. The West went through the industrial revolution and heavy industry is also lacking in many of these countries.

So they are mostly agrarian economies and not so different to how the West was before the Industrial revolution. Back then, poor was the norm in Europe too.

Some of these countries are resource rich in various metals but most of that is a fairly new discovery and requires outside investment to get off the ground. Then you have sovereign risk factors and unstable governments which makes investors shy.