Here I go. First I would like to say to EVERY ONE: CHRIST IS RISEN, INDEED HE IS RISEN!!!
The great Apostasy is a fantasy cooked up by disgruntled Protestants who dislike any form of spiritual authority. The notion of the Catholic and Apostolic Church East and West going into apostasy, gave them the excuse they needed to separate from the Church and form their own religion cooked up in their minds.
This type of reasoning gave rise to a new concept of the church. It was no longer a visible organized structure centered around the Bishop as the shepherd of the Lord’s sheep. It gave rise to the idea of the INDIVIDUAL choosing for themselves what is right and what is wrong. Because of this mindset, people felt free to believe whatever they chose to, relying on some vague notion of the leading of the Holy Spirit.
Disregarding or forgetting History, they were cast adrift in a vast sea of diverse opinions, with only one thing to guide them: THE HOLY BIBLE. The rallying cry became SOLA SCRIPTURA, THE BIBLE ONLY.
After the printing press made the Word of God inexpensive and widely available, everyone could afford one and like one person said, it was in the hand of every plow boy and farmer in the known world.
People began to form their own opinions about Bible interpretation, some choosing this doctrine and others that. This led to great confusion, and people rallied around whatever sounded good to them. This is why there is no cohesion in Protestant theology.
During the time of Joseph Smith the first Mormon Prophet, there began to arise the idea that the New Testament Church had to be RESTORED because it had to be lost. This was the foundation of the various restoration groups, including the LDS Church.
This is my take on why the LDS church arose. There was felt a need for the TRUE CHURCH, and Joseph Smith fulfilled that need in the minds of many people. God bless every one in their search for truth. I have found my home in the Eastern Orthodox Church.
All my love is in Jesus Christ.