Because, don’t take this wrong, but because it’s all made up.
There was no Great Apostacy although I at least give credit that the Mormons had to believe this in order to deny the teachings of the early church.
Where is the evidence of these Hebrew nations in North America?
Why no DNA link in native Americans to Hebrew people?
Where did the Bible come from? Collected during the Apostacy some how?
I have Mormon family. I love them dearly but it is unbiblical to say Jesus abandoned his church and there is no reason to believe in the man made authority of the LDS church.
Continue your search for the truth.
We have writings from the early bishops who were taught directly by the Apostles. I would suggest you read their works.