An inherited ritual is examined by asking for its religious authority. Longevity alone cannot turn every later invention into an authentic part of Abrahamic religion.
The response to alteration has two parts. Where the original monotheistic teaching is established, contradictory later rites cannot simply be declared essential to that teaching. And innovations by subsequent individuals do not automatically possess infallible authority.
This separates historical existence from normative validity. “People have done this for a long time” describes a custom; it does not, by itself, prove that the custom was divinely legislated.