In exploring Eastern Orthodoxy, at some point it struck me that what we consider to be Eastern Orthodoxy in the Modern West is qualitatively different from what Eastern Orthodoxy is supposed to be, and was in earlier centuries: that is, a fully immersive and coherent way of life.
A modern Westerner attending an Eastern Orthodox church once or twice a week and practicing personal devotions between-times just is not at all the same thing as growing-up living under an Orthodox Monarch in a society where Orthodoxy is everywhere you turn.
Something similar applies to Roman Catholicism in the West; although Western Catholicism has not been as integrated a system as sometimes happened in the East, since there always was a secular realm.
And, having noted this, it seems very highly probable that never again will there be the kind of Catholic society that existed in the past.
Which means that Christians are 'all Protestants now' in a sense - all necessarily focused on private devotions as the centre of our Christian life, because there is nothing else for us to be focused-on, hour by hour and day by day.
There just isn't enough of the other stuff of Christian living.
Of course, this is a truly terrible loss of potential, of the highest levels of Holiness; on the other hand it means there is now no strong or Good reason for Christian disunity.