Somehow Christianity has become a nonmystical religion. It’s about a reasonable faith. If we believe the right things, then we are orthodox. Frankly whether we ever actually connect to God or experience His undeniable presence has become incidental, if not irrelevant. We have become believers rather than experiencers. To know God in the Scriptures always went beyond information to intimacy. We may find ourselves uncomfortable with this reality, but the faith of the Scriptures is a mystical faith. It leads us beyond the material world into an invisible reality.
No, the BCP does not respect the tradition of an unchanging liturgy, but then it is a primarily Protestant document, however if you look at what the more Catholic divines of the early Anglican Church thought in regards to liturgy and how they practiced it one sees far greater continuity.
The Prayerbook of 1549 was really not much different from the Mass which preceded it and can be seen as a direct continuance of what went before. The prayers were the same but only rendered in English. Of courses many members of the Church of England, all throughout it’s history have advocated a return to this Prayerbook.
So, of course the Prayerbook as we know it flaunts the idea that the Liturgy should never change but then so much of the Roman rite does as well. The various Liturgies that have existed can hardly claim to be the same as the New Rite as much as the BCP can claim to be a continuance of the Rite of Sarum.
I don’t think I really do believe in organic development of the Liturgies. I really think that once the liturgy was formulated then it should remain as it did, of course the calendars can be added to and the aesthetics of ornaments of the Liturgy can change with fashion. However I don’t think that the liturgy should change with the times unless it is felt that revision (and revision should only be very slight) is need for the betterment of the Church.
Just as the Doctrine of the Church never changes so the Liturgy does not because if the Liturgy does remain the same then it provides a link with our ancestors in faith stronger than anything else the Church can provide.