[delta_p_delta_x]

> before they ran into the regions resource limit and adapted a religion

They didn't 'run into the regions [sic] resource limit and adapt a religion'; said religion was forced upon them by the sword. Iran's state religion (if you could call it that) was Zoroastrianism. There are zero Zoroastrians left in Iran; most of them have fled to... India. And said religion ripped through the Indian subcontinent, too; it is why Pakistan and Bangladesh are separate nations today.