“They are not competitors.”
Shows what you know about Islam.
Yes, they are competitors.
Iran has the “holy city of Qom”, their Shiite shrine where the Twelvers hope the Muslim messiah, the Mahdi, will appear to spread blood and destruction to the infidel.
Saudi Arabia has Mecca, where supposedly Mohammed was handed a moonrock by Allah.
[Allah being a pre-Islamic pagan moon deity..]
So you have the Shias in competition with the Sunnis, Sufi, Wahhabi, etc..
Right, both have the ultimate goal of bringing about a Caliphate with their particular brand of Islam.
So are Catholics and Protestants competitors? Or Jews?
These "competitors" still go on the Haj to Mecca and Medina at the same time. They pray together. 10% of Saudi Arabia is Shi'a. About 90% of Islam is Sunni.