In order to understand the "why" of the modern perversion of the Bible (which is the Word of God) we need to go back to the beginning.
Satan (through the Serpent) in the garden of Eden lied to Eve and deceived her by presenting DISTORTIONS of God's words.
Now the serpent was more subtil than any beast of the field which the LORD God had made. (Gen 3:1) That word *subtil* (subtle) is from the Hebrew עָר֔וּם (a·rum) which in this case means crafty, cunning, sly, tricky, or wily -- marked by skill in deception. And the primary weapon of the Devil against both Christians and non-Christians is DECEPTION. What did Satan do to deceive Eve?
1. PERVERTED THE WORDS OF GOD -- Yea, hath God said, Ye shall not eat of every tree of the garden? Or in modern parlance "Did God really say that you cannot eat of EVERY TREE garden?" We know that God said nothing remotely resembling that, and Eve knew it, but evidently Eve was as eager to play his game as Satan was to deceive her. What God had actually said was the EXACT OPPOSITE -- And the LORD God commanded the man, saying, Of every tree of the garden thou mayest freely eat: But Eve did not tell Satan at once "You are a blatant liar". So he continued with his lies.
2. CONTRADICTED THE WORDS OF GOD -- And the serpent said unto the woman, Ye shall not surely die:. But God had said: But of the tree of the knowledge of good and evil, thou shalt not eat of it: for in the day that thou eatest thereof thou shalt surely die. And again, this lie was allowed to stand, even though it was the EXACT OPPOSITE of what God had said.
3. CONCOCTED HIS OWN DOCTRINE -- For God doth know that in the day ye eat thereof, then your eyes shall be opened, and ye shall be as gods, knowing good and evil. This is the EXACT OPPOSITE of what would happen if Adam and Eve disobeyed God. We know from Scripture that instead of becoming as gods (a) Adam and Eve were driven out of Eden and (b) the whole human race was tainted with the indwelling sin nature, and death was guaranteed to all human beings. This made the need for the Savior a divine necessity.
Beginning in the late eighteenth century unbelieving and rationalistic Higher and Lower Critics began to believe that they were wiser than God ("ye shall be as gods") and began attacking Scripture. The Higher Critics focused on the origin of the texts and *the world behind the texts* and made up some fanciful theories (which have been debunked), while Lower Critics examined the manuscripts themselves. Unfortunately they discovered a few ancient corrupted Hebrew and Greek manuscripts and versions and began to promote them as *better*, *more accurate*, etc. than the majority of manuscripts. But these corruptions were manufactured by heretics and Gnostics who had their own agenda to change the doctrines of the Bible.
Hence their *critical texts* began to reflect the same tendencies by (a) perverting, (b) contradicting and (c) concocting. This was through *conjectural emendations*, deletions, omissions, additions, transpositions, and other changes to the existing Bibles. Thus all modern Bible versions since 1881 are quite different from the Reformation Bibles (including the King James and Geneva Bibles).
And it is true that since the 1960s modern Bible versions have proliferated (and the profit motive cannot be discounted), and doctrines have also been created which have no basis in Scripture. Ultimately, Satan is behind every attack on the Word of God, since Scripture is *the Sword of the Spirit* an one of its functions is to defeat Satan's lies.