One reason that comes to mind is the reliance on the Emperor Pantocrator either in Byzantium or Russia. The Orthodox Church -- except perhaps on its geographical periphery or at some historical fault lines -- had a cooperating state of which Gregory VII would not dream.
Related to that is the expansive nature of Roman social teaching. This is a church that cannot sit still till all quandaries of life: war and peace, church and state, marriage and divorce, contraception and abortion, euthanasia and surrogate parenthood -- are all opined about in a neat doctrine. We are in every bar brawl. I say so with pride. In comparison, and by her own admission, the Orthodox Church is centered around an objective, visible, identifiable well-preserved since the time of the Gospels kernel. There is much less to run from the center for.
Emperor Pantocrator -> Emperor Autocrator
"One reason that comes to mind is the reliance on the Emperor Pantocrator either in Byzantium or Russia. The Orthodox Church -- except perhaps on its geographical periphery or at some historical fault lines -- had a cooperating state of which Gregory VII would not dream."
Until 1453 this was theoretically the case, though in fact it hadn't been really true for some centuries before that. After 1453 most of the Orthodox world was under Mohhammaden oppression. Russia is a different story of course. Your point is well taken though and it seems to me that the way Petrine Primacy developed in the West was a direct result of "facts on the ground" in the West. The task ahead of us all now is to come to an agreement on what that primacy really and practically can mean in a united Church today. Even the Orthodox accept that it is more than a mere primacy of honor .