Dear Ration: thats because Allah was one of many gods of the Arabs..Allah was simply given supremacy over others, and the monotheistic theory took off for its simplicity. Deep down Islam is as polytheistic as any, because it is the nature of man to seek God in all His manifestation. Islam therefore developed more as a doctrine of submission and obedience to a set of commands, claimed to be divine, but clearly coming from Mohammad and his Arab culture.
