Greetings in that Divine and Most Precious Name of Our Lord and Savior Jesus Christ!
Before all those Ecumenism accusations get thrown out I'd just like to say, "Stop Hatin."
We have so many different Patriarchs for the same reason we have many Metropolitans, Archbishops, Bishops, Abbots, and Priests. Simply put, we have a lot of very diverse Christians within Orthodox who have many convergent cultural, economic, political, psychological, emotional, and spiritual needs. The Church is stratified across several layers of Apostolic Succession to fulfill the Apostolic Mission and dispensation as were Commissioned. Now some will say we have many doctrinal, theological, or argumentative differences, and that so and so or such and such a Patriarch or Bishop is the only ONE, HOLY, APOSTOLIC, and TRUE priest of such and such Orthodox. This is silly divisiveness and sectarianism. Ones should be concerned with only the Orthodoxy of their own respective jurisdictions, and mind their business when it comes to others. We should always assume the best of each other, and proffer the sincere benefit of the doubt.
I would say this, that in time when the Church is healed and reconciled in God's Grace, then we shall function as we did say before the splits in the 400s and the 1000s era, when the bishops served as equals. Realistically, it is only when folks get confused to think that the grace of Perfection applies to the clergy beyond the Mysteries themselves that things get twists into sectarianism. Folks mistake the clergy and the Priesthood as in varying degrees of infallibility and this is where we fall. Only the Mysteries themselves are perfect. We should mutually respect each other so long which includes not necessarily stepping on each others toes, as it was in the distant past.