I have a few comments on why I feel why there is such a vast difference in how Christians arrive at the truth,or how I see they percieve the truth. I will ask two questions:
Does the Holy Spirit speak to individuals,which make up the Church? or Does the Holy Spirit speak to the Church,which is made up of individuals?
In the former, Truth is revealed to individuals and then it is lived out in the arena of the whole(the community),in the later the Truth is revealed to the whole(the community) in then is lived out in the lives of individuals in within that community.
The later is where I believe the Orthodox to stand,and the former is where both Protestants and Roman Catholics stand. With Protestants truth is revealed to THE individual,with Roman Catholics the individuals are the Pope,and the Magesterium,excluding the laity. This is where I believe where the divergence occurs.