Ismail’s conversion policy had the following historical outcomes:
Although conversion was not as rapid as Ismail’s forcible policies might suggest, the vast majority of those who lived on the Iranian plateau did identify with Shiism by the end of the Safavid era in 1722.
Hence it is no accident that today Iran’s Sunni minorities are [mostly] concentrated among the countries non-Persian ethnic groups that are scattered along the country’s borders, with their Sunni conationals next door. [yet there is still a good number of Persian Sunnis, particularly in the Fars, Khorasan and Hormozgan province. Up to this day there Persian Sunni cities in Iran, like kookherd, Bastak, Khonj, Evaz or Birjand, Taybad etc. in Khorasan. ]
The Safavid experience largely created the clear line of political demarcation and hostility between Twelver Shiism and Sunnism, even though doctrinal differences had long been recognized. Before the Safavids the Twelvers for many centuries had mostly accommodated themselves politically to the Sunnis, and numerous religious movements combined Twelver and Sunni ideas.
Ismail’s advent to power signaled the end of Sunni Islam in Iran and Shiite theologians came to dominate the religious establishment.
The hierarchical organization of the Shiite clergy began under Ismail.
The current borders between Iran, on the one hand, and Afghanistan and Turkey on the other, date from this time and are not ethnic but religious, opposing Shiites and Sunnis.
The Sunni majority was treated brutally and was most resistant to the Safavids’ conversion policies, which went on at least until the end of the Safavid period.