Aside from the intellectual aspects - the western world had an additional advantage. Combined with the idea that there is one God, and one absolute way that the world was formed, science set out to discover that way.

China, India and the far east were hampered by the concept that there was no controlling deity and no absolutes on the laws of nature. The Middle East as you mention was hampered over time by cosanguinity. The geographical obstructions to the spread of the allele are an aspect I hadn't seen mentioned before, but like continental drift, they seem obvious in hindsight.