"Arabic numbers" are of Hindu origin.
Exactly right. Any "accomplishments" are largely the result of exploiting the existing dhimmi Christians, Jews, Zorastrians, etc. These were the foundation. Particularly in the Ottoman Empire, the backbone of the empire were the Greek and Armenian Christians.
While in general agreement with your post, I believe that the Muslims do NOT consider that the Zoroastrians are 'dhimmi', people of the book, mostly because they were not. Zoroastrianism was an entirely separatge pagan religion, founded roughly in the same period as Buddhism, but in the Persian Empire. It was an ethical religion, and some of its beliefs passed into the Roman West, most especially the worship of the lesser Zoroastrian deity, Mithras. The symbol of Mithraism was a Sacred Bull, and that of Zoroastrianism was the fire.
While accepting Christians and Jews as followers of the same God, Islam gave the Zoroastrians the choice of converting or being executed. To this day islam has a horror of the 'fireworshippers'. As a result, not one Zoroastrian remains alive in the Persian homeland. A number of refugees fled to India, where they remain, and are known as 'Farsi', Hindu for a Persian. The Zoroastrians believe in a good creator god 'Ahura Mazda' and a nearly equally powerful evil god 'Ahriman'. They are known to their Hindu neighbors especially for their practices in desposing of the bodies of the dead. Instead of burying or cremating corpses, the Farsi leave the bodies exposed in walled courtyards, set aside for the purpose, where they can be eaten down to the bones by birds and other scavengers. This does not improve their reputation in the areas of India where they reside.