I would say no. Zoroastrianism seems to have been all too minor without Sassanid authority. Muslim scholars seem fairly ill informed on Zoroastrianism even after conquest of Iran, and this is due to, as al-Tabari mentions, there being only a small percentage of 'true Zoroastrians' the majority of Iran were termed simply 'Majoos' or worshipers of flames or fire. This implies a more archaic Iranian polytheistic tradition, separate from the Sassanid royal dogma of Zoroastrianism, as informed by priest Kartir in the III century CE. Likewise, Mithraism was common and a stronger force in the region after the Arab conquest than Zoroastrianism.
Regarding the Dhimmi question, Zoroastrians were tolerated as in they were not killed immediately. however, depending on the circumstances, they could be forcibly converted and likewise, there was a law that permitted the destruction of any and all sites of worship in Iran that were not Jewish, Christian or Muslim. This was also free for anyone to do, that is, a private person had an Islamic right to destroy any item of worship of Zoroastrian or Iranic origin. This was not too difficult, considering the deep rot at the center of the Sassanid system and its Zoroastrian faith, which had by my opinion, already been decayed beyond and ability to resist Islam.
The religions prevalent in Hindustan were much less reliant upon governmental protection. Zoroastrianism was the royal cult of the Sassanid royalty and a tolerated faith by the Great Houses, if a bit hated. Hinduism of its many types, was a decentralized collection of religious traditions, not tied to the royal elite and self sustaining due to the power of both the local varieties, its immense age, the cultural continuity in the region and the caste system/jaati/varna. The caste system for instance, was so strong that Muslim elites were forced to adopt it and fit within the structure, controlling masses of the populaces with only a slight pivot. Hindustan is also far greater in population than Iran, which is much more sparse, even Mesopotamia is very light in population compared to earlier epochs.