You don't know everything what ancient Church taught.
Many those things that you don't know were revealed again in this dispensation.
We have prophet Joseph Smith. God revealed to him things that were lost.
Those who say that God was always Father and that Son is uncreated did NOT get this idea:
1)from the Bible
2)from God
So, how did he come up with that strange idea that Father was always a Father?
Idea of Heavenly Mother is not strange and it is easy to comprehend. This idea is from God.
A. Everyone knows what the ancient Church taught. Modern churches declare the exact same truth as the first "congregation/assembly" did when they met for the very first time.
Jesus saves.
Jesus is Lord. The Gospel. It's been the same message ever since Jesus walked this earth. Not a jot nor tittle has been lost from the utter simplicity of that defining Gospel Message. I know it.
Phoebe knows it.
Armenian John knows it.
Albion knows it.
ViaCrusis knows it. And so forth and so on. We don't always know which denomination each of us identifies with, but we all share the exact same Gospel, and depend upon God's truth with every part of our being as "Born-again Christians" for it. As far as doctrinal teaching goes, we all know doctrine doesn't save. Jesus does. Both have been continuing biblical concepts of the ancient to modern Christian Church. Always have been, always will be.
B. I'm glad to see your admission that "'you' have your own prophet, JS", being a part of mormonism. That is the actual truth, so thank you for that. Christians, as you know, don't recognize him as such. What's more, we never will. I think you know the many reasons why, so I won't bother to get into them. Many of them have been discussed in this thread already, so why add my voice to the list?
C. Your words cannot be created without "you", so how could you expect God to be any different? Your voice can never be "disembodied" as a separate part of you, can it? It is yours, a distinct part of you. Nobody can express your thoughts the way "you" can. Same with God. Jesus is the "Word" of God, or His "Voice" so to speak. What part of God could, even within mormonism, be "created" without His Word/Voice being a part of Him? Even in mormonism within all its forms recognizes Jesus Christ as the "Word of God". Within Christianity, God is an eternal, uncreated divine Being, so therefore His Word (Jesus) and/or Voice (Jesus) has also always existed as part of Him. Very simple to comprehend. (Jesus' physical body was not created until He was born, as prophecy precisely foretold it would be. Doesn't mean Jesus didn't exist before having a human "body". God is God. He can do anything, having no need for us to "understand" His ways or require our approval in doing what He desires either. If He did, would He be God?)
D. You are right. Nowhere in the bible does it mention something so perfectly essential to all humanity, to innately comprehend our word/voice being a unique part of us and no one else. I cannot think for nor speak for anyone else but myself, just as no one can think or speak for me. It's akin to breathing--one of those things every human "gets" (or should). God never explains "how to breathe" in the bible. Not once. But we all do it. He gave us basic intelligence to grasp certain universal concepts without having to think about them, instead of patiently explaining such things like we are His idiot creation. (I believe you have the same concept within mormonism, "not everything is explained within the bible"? Correct. Some things are so basic to all humanity they are left unsaid. Use it in this instance just as handily.)
E. On the other hand, you are quite wrong when you say the concept of God's Voice/Word (Jesus) is not from the bible. That is clearly stated throughout the bible, actually. God is the Creator, therefore the concept is indisputably from Him. John 1:1 is the most recognized of all related verses that reveal this truth to humanity. If Jesus is God's Word/Voice, therefore Jesus has always existed as God's "Son". Who are we to tell God that His Voice/Word shouldn't be linguistically referred to as "HIS Son" until His "Son" is given a human body in order to call him "Father"? Personally, I'm not that foolhardy to go telling God what He should or should not do. He's the Creator of all language. If it's okay with Him, it should be okay with us, yes? Maybe I should start referring to what I write as my "daughter" (with a little "d", naturally), instead of my "text"? Hmmm..... God does encourage us to be more like Him, after all. Kind of like 'owning your own words'! This world could use more of that one!
F. Maybe you should have added "according to mormonism" when it comes to the idea of a "mother goddess" being "from God"? Judaism nor Christianity has never once found even the barest mention of such a notion within the pages of biblical text we recognize as God's spoken Word. Not for over 13,000 years. Not even within Islam has such a notion ever been discovered in the Q'uran as well. We all do realize the notion definitely being found within Paganism, however.
So, as far as the subject of this thread goes, how could there possibly have been an "apostasy" if the same Gospel Message is still joyfully being declared to the Lost, from the very first congregational assembly right up to this fine Sunday morning in the year 2016 A.D.---BY GOD'S OWN WORD?
Jesus saves! He still does. Jesus is Lord! He always will be.