I'm not sure I buy it... I just don't think things hinge so delicately on individuals. Generally if one person has an idea, thousands of people around them have the same idea. The limiting factor is how many of those thousands have the time, resources, and will to follow through with the idea. The distribution of excess time, resources & will has a pretty strong correlation to environmental & socioeconomic factors.

As for the borders of whatever empire expanded from that region, sure they would have been different. I don't think there would have been an exact correlate of Islam necessarily.

But if you look at the period of ~500s to ~1500s as a golden age for merchant kingdoms in that region, where they built off the intellectual foundations that were spread by rome, I think that was basically inevitable.

I also think it makes sense that something like a religious ideology would be a catalyst for that, to unite so many disparate people in a way they can trust each other and work together in a decentralized fashion.

And for that religious ideology to stick around and take a conservative turn after centuries of antagonism, colonialism, and interference from the west, that also seems like a pretty natural course of events.

The specifics of each country definitely have variance and could have turned out differently. But as you zoom out I think that if trends are happening on a scale of 10s or 100s of millions people, it's got a deeper underlying cause.

I think of it in terms of physics. A person can't lift a huge steel beam by themselves. There's a larger force at play when the beam gets lifted... a larger well of potential energy. The aligning of that well of potential energy to the goal of lifting the beam takes a certain amount of time. One person could lift it by themselves over time if they create a lever and add counterweights, but it would take more time. However a skyscraper? A single person could never build a skyscraper on their own. Think of how much mass is in an army and how much energy is exerted in moving that army across a continent. How can a person deliberately cause so much mass to be moved? They can only do so by tapping into a well of potential energy that already was created. That potential energy must come from somewhere, and when the army moves across the continent, they are expending that potential energy. The process can only continue if the energy well is being replenished. That replenishment is part of the machinery of society. An individual person isn't going to singlehandedly author that machinery in a group larger than the size of an ape troupe. It takes a lot of energy to modify that machinery at the scale of even a small city. A single person can only make minor contributions to the modification of the machinery at the historical scale.