This question is prompted by this comment by /u/Oedium.
What lead to the strong presence of Monasticism both in everyday Christian life, but also in the church hierarchy in Eastern Christianity (or at least Byzantine Christianity) as compared to western traditions?
As far as I can tell, even after the Cluniac reforms, monasticism does not have the same level of presence or power within the western church hierarchy as in the east.
One part of the answer may be that Orthodox bishops are required to be celibate (unmarried) priests, and unmarried priests are usually hieromonks ... parish priests are almost always married, in Orthodoxy. Therefore the Orthodox church hierarchy consists of former monks, which leads to a stronger emphasis on monasticism. In the West, especially after the Gregorian reform (1100s-1200s), priests were not married, and therefore you have a much wider variety of hierarchs (i.e. not just monks).
Just to give a recent real-world example, you can see this in the Orthodox churches within America; in the Antiochian archdiocese, there's a unique case of the majority of bishops having been celibate parish priests, which is a rarity, and this at least partially explains why there's virtually zero emphasis on monasticism among Antiochians in America (two monasteries in the entire country), versus the Greeks (19 monasteries).
This is not an answer - more like a follow-up question, because I have read at least two different authors arguing that the development of monasticism has something to do with the decline of Hellenistic learning. It seems interesting but is it convincing?
From Tirmingham's Christianity Among the Arabs (pp. 66-67),
Constantine realized ... the way to neutralize Christianity was to patronize it. He followed his acceptance of the doctrinal formulation of Nicaea with the declaration that dissidents were scoundrels, enemies of the truth, whose works should be burned. This was a declaration of war on the freedom to interpret. While the Greek controversialists in fact became all the more bitter, Arameans and Copts abandoned any intellectual attempt to reconcile the conflict between the exoteric and esoteric elements in the Christian tradition in order to purse practical ways by which the false duality could be overcome, hence they called it "the Christian philosophy" and "to philosophize" meant "to pursue the monastic way".
And in Judith Herrin's Formation of Christendom there is this argument that the popularity of monastic discipline in the West coincides with the lack of ancient learning (Greek's intellectualism) and vernacular translations (this is what I can find from my notes, I don't have the book at the moment).
I'm really curious if any Late Antique/Christianity scholars can comment on this assessment?