Now now, if you take away the Catholic mythos of Mary as a mediatrix, where will the institution/religion of Catholiciism draw its power?
Well they would still have the Priesthood and their Pope....however they would not have the female figure they need to attract other faiths, who also have female deities, into the Universal Church United they are now promoting.
Unfortunately when a religious group fails to maintain the centrality of Jesus Christ then it's quite natural for any thing else to come flooding in.....and then stick on it some religious meaning for it to be accepted. And as we've seen for centuries 'things" become central, fables abound, and it just grows to something God never intended it to become.
The power comes from the Holy Trinity, God the Father, God the Son and God the Holy Spirit.