Drearyweather,
1) The Aleppo Codex (written around 930 C.E.) is oldest OT copy.
2) The very fact that God permitted the multiple destruction of Jerusalem Temple where scrolls were safeguarded and the destruction of Alexandrian library shows that Scriptures do not belong to Him.
We read in the Bible that revealing the name, Jehovah, is connected with God's miraculous saving of Israelites from Egypt which culminated in parting of Red Sea. This story does not meet the standard of realism because after seeing such a great miracle no one would turn into calf worship telling a single calf "you are our gods who saved us from Egypt." (Ex 32:4, 8, 31)
Yet inventing of God’s name as Jehovah (He Causes to Become) is in agreement with the overall theme of the Bible and human experiences. We see what is new becoming old and decadent as the time passes by. What has become old can be renewed by God Almighty. This means history starts with perfect conditions and remains as one world family for some time, and gradually becomes imperfect when people become egoistic; and a measure of disorder sets in many avenues of life—some of the humans and animals becoming eaters of flesh of other beings and some of the micro organisms turning malevolent and migrating into human bodies causing illness…etc. Each experience teaches us something, and pain-mechanism tells us how to avoid further/future pain, which makes God’s intervention and communication unnecessary on every choice each individual makes. If humans make onward progress taking lessons from pain, God doesn’t have to intervene. But if humans repeat their wasteful acts and situation becomes the worst, then God has to intervene, and “renew” the provisions for life’s enjoyment whenever they deplete/destroy them. (Mathew 19:28) It means God ‘causes himself to become’ the savior of mankind. Hence there is no exaggeration in those writers of OT coining the name Jehovah.