Since the time of Moses, folks had a pretty clear understanding of the exact meaning of Genesis.
It is only since Darwin wrote "Origin of the Species" that the book of Genesis has been considered open for interpretation.
Why, in the course of several thousand years, was no priest bright enough to figure out that Genesis was not written to be read literally?
How did we mere mortals become so intelligent over the last 100 years?
It isn't that we've become "so intelligent".
There is an overlooked significance of the Pentatauch for God's covenant people. The ancient Israelites operated with oral tradition; that is how the Abrahamic Covenant was communicated down through the generations before Moses. When he wrote this stuff down by the command of God that was something that few civilizations/religions had at the time.
God's inspiration of Moses was to inspire a people not with specific, scientifically and factually clear methods of how God did what He has done, but simply to say that He did it. The people who received Genesis 1 were at a level of understanding that necessitated exactly what God gave them. They rallied behind the fact that God did what He did and pronouced it "good".
Looking at the Scripture as a scientific text book is folly. Suggesting that for us to respect Scripture necessitates a 6x24 understanding of Gen 1 is like saying that we have to read the sections of the newspaper exactly the same; I don't read the news in the same way I do the editorial or comics. Does that mean I don't respect the newspaper?
God has given us all we need for faith and salvation and quite frankly I could care less how He created the heavens & earth. I know He did; just as I know He will return "to judge the living and the dead". The details are beyond me and He has left each end of history vague because it is above our paygrade to know specifics.
Rest in that and you'll be practicing a central tenet of all of Scripture; humble servitude to a loving, gracious God.
