Why have most religions fallen into a hollowness…

Why have most religions fallen into a hollowness (or extremism)? The Baha’is have an answer or two;

“…the administration of the Cause is to be conceived as an instrument and not a substitute for the Faith of Bahá’u’lláh…it should be regarded as a channel through which His promised blessings may flow, that it should guard against such rigidity as would clog and fetter the liberating forces released by His Revelation…”

— Shoghi Effendi, The World Order of Bahá’u’lláh, p. 9